Apple ID required in settings

It does not pop up a dialog requesting that you enter your password? Is this your device or did you buy it second-hand? You may have a problem requiring that you restore your device. See:

Have you tried any troubleshooting?

1. Restart: Press On/Off button until the Slide to Power Off slider appears, select Slide to Power Off and, after It shuts down, press the On/Off button until the Apple logo appears.
2. Reset: Press the Home and On/Off buttons at the same time and hold them until the Apple logo appears (about 10-15 seconds).
3. Restore: Connect your iPhone to iTunes on your computer, backup, and then select Restore to Factory

It means you need to Tap Settings > iCloud > Your name > Enter your Apple ID and password. You need to use the Settings app on your main screen, not in the program.