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Forms Group 10 min read

How to Create Fillable PDF Forms (AcroForm)

Turn any static PDF into an interactive, fillable form using Utilvo's Forms group. The group ships with 10 field types — text inputs, checkboxes, radio buttons, dropdowns, listboxes, date pickers, signature fields, initials fields, and image fields — all rendered as standards-compliant AcroForms dictionaries so the file opens identically in Acrobat, Foxit, and macOS Preview.

Click-to-place works on every page — including inserted blanks

Drop fields on any existing page or a freshly inserted blank page.

Launch Editor

What Is AcroForm?

AcroForms is the original interactive form technology baked into the PDF standard (ISO 32000-1, §12.7). It defines a small set of field dictionaries — /Tx for text, /Btn for buttons/checkboxes/radios, /Ch for choice lists, /Sig for signatures — each with a consistent set of properties (position, size, default value, appearance stream). Utilvo emits these dictionaries directly using pdf-lib, which is why the exported file behaves identically to one produced by Acrobat.

AcroForm vs XFA — what Utilvo supports

Utilvo uses AcroForm — the PDF 1.7 native form model. XFA (XML Forms Architecture) is Adobe's legacy XML-based alternative used in some government and tax PDFs. Utilvo does not support XFA authoring — but in practice AcroForm is the universal format: every modern PDF reader parses it consistently. If your source PDF uses XFA, save it as AcroForm in Acrobat first, then load it into Utilvo.

The 10 Form Fields at a Glance

All 10 fields follow the same click-to-place pattern: select the tool in the Forms group, click on the page, the field appears at the cursor. After placement, a green selection box with a red × delete handle and a Move button appears, allowing immediate repositioning. Click anywhere else to deselect.

Text InputFORM-TEXTText

Single-line text input. Best for names, emails, IDs, phone numbers.

default size: 100×18 pt

Multiline TextFORM-MULTILINE-TEXTText

Free-form paragraph text. Best for comments, addresses, descriptions.

default size: 110×40 pt

CheckboxFORM-CHECKBOXBoolean

Toggleable on/off. Best for consent, agreements, opt-in.

default size: 12×12 pt

Radio ButtonFORM-RADIOChoice

Mutually-exclusive choice within a group of two (Option 1 / Option 2).

default size: 12×12 pt

DropdownFORM-DROPDOWNChoice

Compact single-select. Three default options.

default size: 100×18 pt

List BoxFORM-LISTBOXChoice

Scrollable multi-row list. Four default items.

default size: 100×22 pt

Date PickerFORM-DATESpecial

Native PDF date field with calendar UI. Format: YYYY-MM-DD.

default size: 100×18 pt

Signature FieldFORM-SIGNATURESignature

Empty signature placeholder field. Stores the user-supplied signature image when filled.

default size: 110×32 pt

Initials FieldFORM-INITIALSSignature

Smaller signature variant for initials beside each signature line.

default size: 60×25 pt

Image FieldFORM-IMAGESpecial

Allows the user to upload an image (JPG, PNG, WebP) when filling the form.

default size: 90×70 pt

Field-by-Field Walkthrough

Each field below documents what the field looks like, when to use it, and what the default value is. The first figure shows the most common pattern — text input placement.

Field 1

FORM-TEXT — Text Input

Single-line text input. Emitted as a /Tx field with default dimensions 100×18 pt. Use for short fields: name, email, phone, ID number, ZIP code. The user types directly into the field when filling; default value can be set in the properties panel.

Text input form field placed on a PDF page
Figure 1. FORM-TEXT placed on the page — single-line input ready for the user to type into.
Field 2

FORM-CHECKBOX + FORM-RADIO — Boolean and Choice

Both fields render as a 12×12 pt square. Checkbox is independent — each box toggles on or off, perfect for consent or "I agree" lines. Radio is grouped — placing two radios on the same page with the same name creates a mutually-exclusive group: clicking one clears the other. Utilvo places radios with default options "Option 1" and "Option 2"; rename them in the properties panel.

Checkbox and radio button form fields placed on a page
Figure 2. Checkbox + radio pair — the checkbox is independent; the two radios share a group name.
Field 3

FORM-DROPDOWN — Compact Single-Select

Closed-list single-select. Default 100×18 pt with three options. Click to open, click an option to select. Use when you have 3–10 mutually exclusive choices and the user should only see one at a time (e.g., country, state, department).

Dropdown form field with three options visible
Figure 3. Dropdown opened — three default options, click one to set the field value.
Field 4

FORM-LISTBOX — Scrollable Multi-Row List

Open-list single-select. Default 100×22 pt with four items, scrolled. Use when you want users to see several options at once without opening a menu (e.g., choice of course, choice of office).

Listbox form field with multiple visible items
Figure 4. Listbox with four default items — all visible at once, click to select.
Field 5

FORM-DATE — Date Picker

Native PDF date field. Default 100×18 pt, format YYYY-MM-DD. When the user fills the form, the PDF reader opens a calendar widget for selection. Stored as a /Tx field with the format flag set — so it round-trips through any conformant reader.

Date field with calendar widget visible
Figure 5. Date field — calendar widget opens automatically when filling.
Fields 6 & 7

FORM-SIGNATURE & FORM-INITIALS

Empty signature placeholder fields. Signature is 110×32 pt (roughly the size of a real signature line); Initials is 60×25 pt (compact, for per-page initials). Both render as a clickable placeholder that opens a signature capture dialog when filling.

Signature and initials form fields placed on a page
Figure 6. Signature field (top, wider) and initials field (bottom, compact) — empty placeholders.
A note on "signature" — AcroForm vs PKCS#7

AcroForm signature fields are visual signature containers: the user signs inside them and the captured raster signature is stored in the field's appearance stream. They are not PKCS#7 cryptographically verifiable signatures (the kind issued by a CA and stored in the PDF's /Sig dictionary). For PKCS#7 signing, use Acrobat or a dedicated tool after authoring the form.

Multiline Text

110×40 pt by default. Wraps text automatically. Best for comments, descriptions, addresses. The isMultiline flag is set on the underlying AcroForm dictionary so the reader knows to allow line breaks.

Image Field

90×70 pt by default. Stores a JPG, PNG, or WebP uploaded by the form filler. Useful for ID photos, signature images embedded in forms, or any case where the user needs to attach a picture.

Edit Fields Mode vs Fill Mode

Utilvo ships with two interaction modes for forms, switched by the toolbar's Select tool toggle:

  • Edit Fields Mode (default) — click a field to select it; drag to move; use the green handles to resize; click the red × to delete. Use this when authoring or modifying the form.
  • Fill Mode — click a text field to type into it; click a checkbox to toggle; click a dropdown to open. Use this when previewing or filling the form.

The mode toggle is in the top toolbar — look for the cursor/cursor-pencil icon next to the field tools.

The Field Properties Panel

Select any field with the Select tool and open the right-side Properties panel. Every field exposes a common set of properties plus field-type-specific options.

Common Properties (all 10 field types)
  • Name — internal identifier used when exporting form data as FDF/JSON. By default auto-generated as field_1, field_2, etc.
  • Tooltip — short hint text shown on hover in any conformant reader.
  • Read-only — when on, the field displays its value but cannot be edited by the user.
  • Required — when on, the form cannot be submitted (or the field cannot be exported) without a value.
  • Page — read-only display of the page index this field is bound to.
Type-Specific Properties
  • Text / Multiline — defaultValue, maxLength, isMultiline, isPassword, isComb (for fixed-width character cells like a US Social Security Number).
  • Checkbox — isChecked (initial state), style (check / circle / cross / diamond / square / star).
  • Radio — options[] with { label, value }, groupName (radios with the same group are mutually exclusive).
  • Dropdown / Listbox — options[], isMultiSelect (listbox only), defaultValue.
  • Date — dateFormat (YYYY-MM-DD / MM/DD/YYYY / DD/MM/YYYY).

Authoring Workflow — Five Steps

  1. Open your PDF. Drop the static PDF into the editor. If it's a scanned image, run OCR first (see the Text guide for why Utilvo itself does not bundle OCR).
  2. Switch to the Forms group. Pick FORM-TEXT, FORM-CHECKBOX, etc., and click on the page where each field should appear.
  3. Configure each field. Click the field to select it, then edit Name, Tooltip, Required, and any type-specific options in the right panel.
  4. Add a signature line. Drop a FORM-SIGNATURE where you want the user to sign. Add FORM-INITIALS beside each clause that requires initials.
  5. Export. Use File → Download to save the AcroForm-enabled PDF. The form fields are preserved across readers and can be filled in Acrobat, Foxit, Preview, or any conformant tool.

Limitations to keep in mind

  • • JavaScript actions are not supported. Utilvo emits the static AcroForm dictionaries — it does not inject calculation scripts, validation scripts, or formatting scripts. If your form needs these, author the form in Acrobat Pro, then load the static layout into Utilvo for visual edits.
  • • XFA forms cannot be authored. Utilvo only emits AcroForm. If your source PDF uses XFA, re-save it as AcroForm in Acrobat first.
  • • Field appearance styles are read from the source PDF where possible; otherwise Utilvo falls back to a default Helvetica-style appearance. Custom fonts in field labels are not supported.

Further Reading

Frequently Asked Questions

Which AcroForm field types are supported?

Text (/Tx), Multiline Text, Checkbox (/Btn), Radio, Dropdown (/Ch), Listbox (/Ch), Date picker, Signature (/Sig), Initials, and Image. All conform to ISO 32000-1.

Can I add fields to a page that wasn't originally a PDF page?

Yes. If you used Insert Blank Page to add a page, click-to-place still works on it. The field is written into the form-field dictionary on that page.

Will the form work in Acrobat and Foxit?

Yes. Utilvo writes the same AcroForm dictionary structure that Adobe's products emit, so the output opens cleanly in every compliant viewer.

Can I tab between fields when filling?

Yes. Each field receives a deterministic tab order based on its placement sequence. Pressing Tab inside the editor (or in Acrobat) advances to the next field.

Continue to the Pages Group

Next up: page management operations and header/footer/Bates configuration.

Read: Headers, Footers & Bates