If you would like to remove the YouMail application from your device, there are two ways:
Find the YouMail app on your homescreen and hold it down until a little pop up appears and just tap "Uninstall.
The other way is through the Google Play Store:
1. On your Android device, tap on the Google Play app, tap the 3 bars in the search bar and tap "My apps & games".
2. Tap on Installed, then find and select the YouMail app, then tap Uninstall
3. You can always go back and reinstall the YouMail app at any time.