Are you asking for a way to share a PDF document with form fields and/or comments that remain editable after sharing?
By default, Acrobat Reader will share a copy of a PDF document without "flattening".
Open a PDF document that you would like to share.
Tap the Share icon in the top bar.
Tap "Share a Copy". Sign-in is not required for "Share a Copy".
Select an option for sharing from the iOS Share sheet. Examples: Mail, Gmail, AirDrop
A recipient can fill out form fields or add comments to the PDF copy.
For Acrobat Reader 18.12.00 or later, please make sure that the "Share a Flattened Copy" option in Settings > Preferences is disabled before sharing. (The "Share a Flattened Copy" option is disabled by default. But you may have enabled the option at one point.)
Please let us know if you have additional questions.