Dark mode is supported on devices having Android 10. If you have a device having version 10 then you can disable Adobe Acrobat in dark mode by simply turning off the dark mode theme from system’s Settings. Follow the steps mentioned next to do the same: Open Settings app -> Display -> Dark theme -> toggle it OFF
You can also turn off the dark theme if you’re using device with Android 9 or above. Just turn off the Night Mode settings from the notification tray. Hope this helps.
Hope you are doing well and sorry for the trouble. As described you want to disable the Acrobat Reader Mobile app dark mode.
Please open any PDF file in Acrobat Reader Mobile app and click on the View Settings icon on the top (next to liquid mode) and toggle to turn off the Night Mode, similar as shown below