To insert a watermark in MobiDocs on your Android device, first make sure you're in Edit mode by tapping the pen icon in the lower right corner of the screen. Then:
1. From the Home drop-down menu go to the Design tab and select Watermark.
2. Choose a predefined watermark.
Note that it is not possible to create a custom text watermark.
To remove a watermark in MobiDocs on your Android device:
1. Open Design tab.
2. Tap Watermark, and then Remove Watermark.