Re: free app to modify pdf files

On Wed, 18 Jun 2025 01:10:44 +0200, sobriquet wrote :

Op 17/06/2025 om 20:21 schreef Arno Welzel:

sobriquet, 2025-06-17 13:27:
 

Op 15/06/2025 om 19:05 schreef Arno Welzel:

sobriquet, 2025-06-14 19:57:
>

What's the best free app to modify pdf files on android?
So not just viewing a pdf file, but actually making changes in it, like
filling out a form with additional information.

>
Filling out forms is not "modify" - it is just filling out a form in the
PDF and storing the result.

>
Modify has the general meaning of "making changes" as one of its
connotations. So if you change anything about a pdf file, like filling
a pdf form, that can be understood as modification.

 
Yes, but you do *not* change the PDF itself. You just enter something in
form fields provided in the PDF. And you can then save the PDF with the
filled form. But when you open it again you will see, that the form
fields are still there and can be changed again - but nothing else,
since you will not change the PDF.
 
It's like filling a form on a website - you do not change the website
itself just by filling a form and sending it.
 

 
It depends how you interpret "change". If you fill out a form I would
say you change the form from an empty form to a form that has been
filled out. Also, it's natural to think of it as modifying the pdf
file, since the file attributes like "date last modified" will
typically change, while it wouldn't change if you just read the
pdf file without making any changes to the file.

I'll agree with anyone who makes a logically defensible statement, no
matter who he is, and I'll disagree with anyone whose statements are not.

Personally, I've been "editing" PDF files for decades, where I will agree
with Arno that most people don't consider filling out PDF forms as
"editing", although technically, any change in the hash is editing.

The reason it matters is simply that the OP needs to be clear on the
problem set because the mix of programs/apps which fill out form fields is
vastly greater than the mix that does actual edits to the text in the PDF.

In addition, I would *never* think of converting a form-field PDF to
another format to fill out the fields (for the same reason as above).

If I wanted to make edits to text inside a PDF (i.e., not just fill out
form fields), I'd use the tools I already described previously.

If that PDF was simply a scan, then I'd convert the PDF to an image format
and change the image as needed, and then convert back to PDF.

I have decades of experience doing this, which is why I say emphatically
that filling out a field is a completely different problem set than actual
text editing of a PDF (or image editing of a scanned PDF).

I could be wrong though... as I did say in the very beginning I didn't know
of a good solution to the user's stated problem on the Android ecosystem.