Infinite Learn is instructive. So you can write the words what you want to memorize. And then study-->chapter-->start, the words that you type will appear on the screen even if you close the application. And a lot of options in the Settings.
The easiest memorization app to memorize for everything.
Pro version from Infinite Learn Settings:
★Stay on Screen★
You can configure the settings as desired.
★★★★★ Important Notes ★★★★★
1- Turn off battery optmism for Android 7 Nougat, Android 8 Oreo and later
2- Applications -> Infinite Learn -> Enable Autostart for Android 7 Nougat, Android 8 Oreo and later
3- Enable Infinite Learn Notifications
More details ABOUT -- SUPPORT in App