How to Fill and Sign a PDF Form Online

The PDF Form Problem

PDF forms are everywhere. Tax forms, job applications, insurance claims, medical intake forms, rental applications, government paperwork, school enrollment forms — if a company or institution needs information from you, there is probably a PDF form involved.

The problem is that many PDF forms were designed to be printed and filled out by hand. Even forms with digital fields can be frustrating to work with if you do not have the right tools. And once you have filled out the form, you still need to sign it.

This guide shows you how to fill and sign any PDF form online, step by step.

Types of PDF Forms

Not all PDF forms are created equal. Understanding what type you are dealing with helps you choose the right approach.

Interactive PDF Forms (AcroForms)

These forms have built-in fillable fields. When you click on a field, a text cursor appears and you can type directly. You can usually identify these by the blue or highlighted input areas. Interactive forms are the easiest to work with — any PDF reader can fill them out.

XFA Forms

XML Forms Architecture (XFA) is an older form format created by Adobe. XFA forms only work properly in Adobe Acrobat. Most other PDF readers and browser-based tools cannot render XFA forms correctly. If a form is not displaying properly, it may be an XFA form.

Flat PDF Forms (Non-Interactive)

These are essentially images of forms — the "fields" are just blank spaces in the document layout. There are no interactive elements. You need to place text on top of the document to fill these out, which is where text overlay tools come in.

Method 1: Fill and Sign Online (Works for All Form Types)

The most versatile approach uses a browser-based tool that lets you add text and signatures as overlays on any PDF, regardless of the form type.

Step-by-Step with SigPDF

1. Open SigPDF in your web browser on any device
2. Upload the PDF form by dragging and dropping it
3. Add text to each field:
   • Click on the area where you need to type
   • Use the text tool to enter your information
   • Adjust the font size to match the form's field sizes
   • Repeat for each field (name, address, date, phone number, etc.)
4. Add your signature:
   • Click "Add Signature"
   • Draw your signature with your mouse or finger
   • Click the signature line on the form to place it
5. Add the date next to your signature using the text tool
6. Download the completed, signed form

This method works with all three form types because you are adding text and signatures as visual elements on top of the PDF. The form does not need to have interactive fields.

Why This Approach Works Best

• Universal — Works with interactive forms, flat forms, and even scanned paper forms
• No software — Runs in your browser on any device
• No account — No registration or email required
• Private — Your form data never leaves your browser when using SigPDF

Method 2: Adobe Acrobat Reader (Desktop)

Adobe's free PDF reader can fill interactive PDF forms and add signatures.

How to Do It

1. Download and install Adobe Acrobat Reader (free, ~200 MB)
2. Open the PDF form in Acrobat Reader
3. If the form has interactive fields, click on each field and type your information
4. For non-interactive forms, go to Tools > Fill & Sign
5. Click where you want to add text and type
6. Click "Sign" to add your signature
7. Save the completed form

Limitations

• Requires downloading and installing software
• Requires creating an Adobe account
• Works best with interactive forms; the Fill & Sign tool for flat forms can be finicky
• Cannot fill XFA forms in the free version on some platforms
• Files may be processed through Adobe's servers

Method 3: Browser Built-In PDF Viewer

Most modern browsers (Chrome, Firefox, Edge) have built-in PDF viewers that can fill interactive form fields.

How to Do It

1. Open the PDF form in your browser (drag it into a browser window or right-click > Open With)
2. Click on the interactive form fields and type your information
3. Some browsers have a signature feature, but support varies
4. Save or print to PDF

Limitations

• Only works with interactive PDF forms — cannot add text to flat forms
• Signature support is inconsistent across browsers
• Limited text formatting options
• No ability to add text outside of designated form fields

Tips for Filling PDF Forms

Matching the Form's Font

When filling a flat (non-interactive) PDF form, try to match the font size and style of the existing text in the document. This makes the completed form look professional. In SigPDF, you can adjust the text size to match the form fields.

Handling Checkboxes

Some forms have checkboxes or radio buttons. For interactive forms, you can click directly on them. For flat forms, use the text tool to type an "X" or a checkmark character in the checkbox area.

Dealing with Date Fields

Date fields come in various formats. Look at the form for guidance — it usually specifies MM/DD/YYYY, DD/MM/YYYY, or a similar format. Match whatever format the form indicates.

Multi-Page Forms

Many forms span multiple pages. In SigPDF, you can navigate between pages and add text and signatures to any page in the document. Make sure you fill out every page, including any sections on the back of the form that you might miss.

Saving a Copy

Always save a copy of the completed form for your records before sending it to the requesting party. If a dispute arises later, your copy serves as proof of what you submitted.

Common Form Types and Where You Encounter Them

Government Forms

Tax forms (W-4, W-9, 1099), passport applications, Social Security forms, and other government paperwork. These are often flat PDFs that need to be filled with text overlays.

Medical Forms

Patient intake forms, consent forms, HIPAA authorization forms, and insurance claims. Medical forms frequently contain sensitive information, so using a privacy-focused tool is important.

Real Estate Forms

Rental applications, lease agreements, inspection reports, and property disclosures. These forms usually require signatures and dates alongside filled-out fields.

Employment Forms

Job applications, onboarding paperwork, benefits enrollment, direct deposit authorization, and I-9 forms. Many of these include sections where you need to both fill in information and sign.

Financial Forms

Account opening applications, loan paperwork, beneficiary designations, and investment account forms. Accuracy is critical here — double-check every field.

What About PDF Form Creators?

If you are on the other side — creating PDF forms for others to fill out — consider making your forms interactive with fillable fields. This makes them easier for recipients to complete and reduces errors. Adobe Acrobat Pro, LibreOffice, and various online tools can create interactive PDF forms.

For recipients who just need to fill and sign what they receive, SigPDF handles any PDF form regardless of how it was created.

Fill and Sign Your Form Now

Stop printing forms, filling them out by hand, scanning them, and emailing them back. Open SigPDF, upload your PDF form, fill in your information, add your signature, and download — all in a couple of minutes with no account required.

Fill and Sign Your PDF Form →