Hello Steve,
I hope you are doing well. As per the above description and screenshot, I understand that you have a notification mark on Acrobat and are unable to get it to disappear.
Let's try with a few steps and check if it works:
1. Open Acrobat Reader Mobile-> Click on the Notification Bell icon on the top right beside the profile Icon;
2. If this does not help; check for any updates available on the App Store;
3. Go to Settings App on your phone-> Acrobat-> Notifications-> Disable the option to allow notification once.
[Once disabled, check whether you still get the red dot with number 1 on the app or is it gone. If gone, enable notifications again and it should be good]
Let me know if any of the above steps help.
Thanks,
Souvik.