Managing app permissions on device
If you want the system to ask each time which of the two apps to use for opening a supported URL, adjust the permissions for both apps:
Open the Settings app on your device.
Tap Apps (or Apps & Notifications).
Find your Form.com / Form.com Classic app, tap it and go to the App Settings section.
Tap on Set as default, and in the screen that opens, set the Go to supported URLs parameter to 'Always ask'.
Make sure that you do this for both Form.com apps installed.
If you want to use one of the two apps at all times:
Open the Settings app on your device.
Tap Apps (or Apps & Notifications).
Find your Form.com / Form.com Classic app, tap it and go to the App Settings section.
Tap on Set as default, and in the screen that opens, set the Go to supported URLs parameter to 'In this app' (this app will be your default).
Go to the Set as default app setting in the second app, and set the Go to supported URLs parameter to 'In other app'.