In most cases, Adobe PDF files contain static data, not intended for other users to edit. PDF forms, however, can have editable text boxes, allowing you to fill out the form without having to print it ...

"When I was filling in an application form from a British organisation, there are two items "Initials" and "Family Name" which I think have similar meanings. So could you explain the differences ...

So I made a PDF form for work that the whole company is supposed to use, but (silly me) didn't realize that Acrobat Reader CAN'T save the PDF with the changes to the form fields! In other words: ...

The application "Preview", which is used for viewing images as well as PDF files, has support for entering text into editable fields in PDF documents. This is convenient for entering data into forms, ...