Whether you're starting fresh or working with a PDF you already have, MobiPDF lets you build interactive forms that others can fill out electronically — no printing, scanning, or manual data entry required.
This article covers two scenarios:
- Creating a brand-new fillable PDF from scratch
- Adding fillable fields to a PDF you already have (including forms that aren't currently interactive)
Option 1: Create a fillable PDF from scratch
If you're working with sensitive information and want to control exactly what fields users can edit — or you simply want a clean, purpose-built form — starting from a blank document is the way to go.
Before you start: plan your form
A little planning up front saves a lot of cleanup later. Here are two things worth thinking through before you add a single field:
1. Text fields vs. interactive fields
Consider what kind of data you actually need:
- Text fields work best for open-ended answers, like names, addresses, or comments.
- Interactive fields — checkboxes, radio buttons, dropdown menus — are better when you want standardized, specific answers and a smoother experience for the person filling out the form.
2. Form logic and validation
Think of these as the "rules" your form follows:
- Required fields — which sections must be completed before the form can be saved?
- Data validation — does a phone number need exactly 10 digits? Does a date need to follow MM/DD/YYYY?
Setting these rules up front means fewer mistakes for users and more complete, usable submissions for you.
Steps to create your form
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Open MobiPDF and go to Create → Blank Document.
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Choose your paper size and orientation, then click OK.
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Click the Forms tab in the top tool ribbon.
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Click any available form element and place it anywhere in your document.
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Name each element whatever makes sense for your form.
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Need more control? Click All Properties to access advanced settings (like required fields or validation rules).
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Keep inserting, customizing, and rearranging elements until your form is ready, then save to confirm your changes.
Option 2: Add fillable fields to an existing PDF
Already have a form — maybe a scanned document or a PDF that isn't interactive yet? You don't need to start over. MobiPDF lets you manually add interactive elements directly on top of your existing content, turning any static form into one people can fill out electronically.
This works great for:
- Non-fillable PDFs (like scanned paper forms) — simply place interactive fields over the existing text, checkboxes, or signature lines.
- Editable PDFs — replace existing text boxes or fields with proper interactive form elements for a more functional, polished result.
In both cases, you can freely position and resize each element so it lines up neatly with your document's existing layout.
Available form elements
Click into each guide below for step-by-step instructions on adding that specific element:
By placing the right combination of these elements over your document, you can turn virtually any PDF into a fully fillable form — tailored exactly to your needs.