License code is only for the dmg version downloaded from our website. If you can't find "Enter License", please make sure that you use PDF Reader Pro dmg version.
If there are different versions of PDF Reader Pro on your device, we recommend that you uninstall all, restart your device, and redownload PDF Reader Pro from here.
Then apply your license code:
1. Click PDF Reader Pro -> Enter License at the upper left.
2. Enter the license code and click Continue to activate.
Note: If you can't find "Enter License", please download PDF Reader Pro.dmg.
Because you don't need to enter license code if you download it from Apple Store.