Filling in forms when they are pdfs

Hi. I have been asked by a charity ( to design some fillable forms that can be sent as pdfs to volunteer fosterers, who then fill them in and send them back. All went well until I tried the first form on my Android phone (most people use Smartphones to access internet). I couldn’t enter text in any of the fields. I downloaded Acrobat Reader and that worked fine, except there is no save option on the free version. Can anyone recommend a free app for Android and iPad (iphone works fine with iBooks) that is simple and secure for anyone to fill in and save pdfs?

This is not a LibreOffice question. It is about phone aps.
Not knowing much on this I tried anyway. Simple search states first:

-    On your Android device, open the Google Drive app.
-    Tap the PDF that you want to fill out.
-    At the bottom right, tap Edit. Form Filling . ...
-    Enter your information in the PDF form.
-    At the top right, tap Save. To save as a copy, click More.

Did not test.

Also found one for Acrobat Reader →
You stated it did not work but I tried anyway. Simple form with two text fields and couple of fixed words.
Got to filling out the form. Instructions say:

  • Touch the pencil icon at the bottom of the screen, then select edit PDF.
  • Fill in the form and touch done at the top of the screen.

The editing worked but could not find Done at the top. There were three vertical dots in upper right corner. Selected that. Then in that list found Save a copy. Selected that, saved on local file then sent to my desktop. Worked fine.
I’m sure there are other methods available also.

Thanks. I will give the Adobe Acrobat Reader another go.