Hi @Meibin29280770r03a,
Hope you are doing well. Sorry about your experience.
Would you mind letting us know the error or the issue you see when inserting a signature?
You can try the given steps to insert a signature on a document (given that the document is not read-only or locked):
- Open the Acrobat mobile app on your device.
- Open the PDF document that you want to sign.
- Tap the "Edit" icon (pencil icon) in the top right corner of the screen.
- Tap on the "Sign" (pen icon) at the bottom of the screen.
- Choose "Add Signature" from the options presented.
- Follow the on-screen instructions to create your signature. You can either sign using your finger or stylus or choose an existing signature from your library.
- Once you have created your signature, place it where you want it to appear in the document.
- When you are finished, tap "Done" in the top right corner of the screen to save your changes.
Hope this helps.
-Souvik