How to make a PDF fillable without Adobe Acrobat
You do not need Acrobat. A PDF becomes fillable when it carries form fields, and you can add those in a browser for free: upload the PDF, mark where each answer belongs, and share the link. Whoever receives it types into a web form, and you get the completed PDF back.
What does "fillable" actually mean in a PDF?
A fillable PDF is one that carries an AcroForm. AcroForm is the interactive-forms structure defined in the PDF specification: a dictionary in the file that lists named widgets, each with a type, a position on a page, and a value. When you type into a fillable PDF you are writing a value into one of those named entries.
The artwork is separate. A PDF page is a stream of drawing instructions — set this font, place this text at these coordinates, stroke a line from here to here. Boxes and ruled lines are drawings. They are not fields, and nothing about drawing a rectangle creates one.
That is why a document can look exactly like a form and accept nothing. If the file has drawings and no AcroForm, it is flat. Why can't I type in this PDF? works through the three reasons a file refuses input and how to tell them apart.
Why Acrobat is not the only answer
Acrobat Pro is a desktop PDF editor, and adding AcroForm fields is one of the many things it does. That is a real capability, and for a long time it was the only practical way to get it.
The problem is what it costs and what it assumes. Acrobat Pro is a subscription, billed monthly, per person. If you make one fillable form a year — a tenancy application, a job application, a permission slip — you are paying for a professional publishing tool to solve a ten-minute problem.
The bigger assumption is on the other end. Adding AcroForm fields makes the PDF typeable, but only for a recipient whose reader honours those fields. Preview on a Mac handles them inconsistently. The built-in viewers in Chrome and Edge are better than they used to be but still lose entered data if the file is reopened rather than saved properly. On a phone, most people open a PDF attachment in a viewer that renders the page as an image. They can read it. They cannot type in it.
So even after you have paid for Acrobat and done the work, you have handed the recipient a file whose success depends on software you do not control.
What are the free ways to make a PDF fillable?
There are three routes, and they differ in what they ask of the recipient.
A desktop PDF editor. LibreOffice Draw and a handful of open-source tools can insert AcroForm widgets and save the file. Free, but you still end up emailing a PDF, so you inherit every reader problem above.
An online PDF editor that returns a file. You get a fillable PDF to download and send. Same outcome, same dependency on the recipient's reader.
A browser tool that returns a link. You place the fields, and instead of a file to attach, you get a URL. The recipient fills a web page, and the completed PDF comes to you. This is the route that removes the reader problem rather than working around it, because nobody but you ever opens a PDF editor.
Add the fields in your browser
The browser route has three steps and no install.
Upload the PDF. Use the document you already send people. It does not need to be redesigned or exported in any special way. Before you start, it is worth knowing what you are holding: the free fillable PDF checker counts the form fields in a file. A count above zero means somebody already did this work, and your trouble is more likely a reader that will not honour the fields than the file itself. A count of zero means they have never existed, and no amount of clicking will summon them.
Place the fields. You mark a rectangle wherever an answer belongs and say what kind of answer it is: a line of text, a date, a number, an email address, a choice from a list. Give each one a clear label, because the label is what the recipient reads. You do this yourself, box by box — there is no step where the software reads your layout and guesses. That is less tedious than it sounds, mainly because it is work you do once for the document rather than once per recipient.
Share the link. The form gets a URL. Email it, put it in a message, print it as a QR code on a poster at a front desk. There is no attachment. How to send a PDF for someone to fill out covers what to do with that link once you have it.
Can I do this on a phone or tablet?
You can complete a form on a phone. Building one is a different job. Placing fields means dragging small rectangles onto a page at precise positions, and that is much easier on a screen where you can see a whole A4 page at readable size. Build on a laptop; send to anything.
What the person filling it in sees
They see a web page. The fields you placed appear as ordinary form inputs with your labels above them, laid out top to bottom, sized for whatever screen they are holding. Required fields are marked. A date field opens a date picker rather than asking them to guess a format. An email field rejects an address with no @ in it before the form goes anywhere.
Nothing downloads. There is no app to fetch, no account to create, no "open in" step where a file disappears into a downloads folder. Someone can complete a tenancy application on a bus, or a new starter can do their emergency contacts on the sofa the night before they begin. That is the whole difference: you have removed the requirement that they have the right software, and replaced it with the requirement that they have a browser.
Getting the finished PDF back
Submitting does not send you a summary of what somebody typed. Their answers are printed into your PDF, in the spaces you chose, and that file is what arrives. One completed PDF per response, in the layout you already use.
Those PDFs collect in one place, under the form they came from, so there is no inbox to search and nothing to reassemble from attachments. You can open one, print it, forward it, or file it exactly as you would have filed a returned paper copy.
Worth saying plainly, since the point here was avoiding a subscription: nothing about that file is proprietary. It is an ordinary PDF. It opens in whatever reader is already on your machine, prints on any printer, and attaches to an email like any other document. You have skipped buying an editor without ending up with a format only that editor can read.
Start from a template instead
If you do not have a PDF yet, do not make one just to have something to upload. There are ready-made forms you can send today, already built with the fields placed. Look through the HR and hiring templates if you are onboarding someone — the job application form and the new hire information sheet cover most of a first week between them. Edit the labels, remove fields you do not want, and send it in the same sitting.