How to remove a line across my I pad screen

Hi Sahar zidan,

Thanks for visiting Apple Support Communities.

If you see a line on your iPad screen, I recommend restarting and then resetting your iPad:

Restarting your device

1. Press and hold the Sleep/Wake button for a few seconds until the red "slide to power off" slider appears, and then slide the slider.
2. Press and hold the Sleep/Wake button until the Apple logo appears.

Note: Reset your device only if you are unable to restart it.

Resetting your device

Press and hold the Sleep/Wake button and the Home button together for at least ten seconds, until the Apple logo appears.

You can find the article with these steps here:

iOS: Turning off and on (restarting) and resetting

http://support.apple.com/kb/ht1430

If you are still experiencing the same issue, I recommend resetting all settings next:

Go to Settings > General > Reset, then choose Reset All Settings: All your preferences and settings are reset.

Reset iPhone settings

http://help.apple.com/iphone/7/#/iph7a2a9399b

If the issue persists, the last thing I recommend is backing up and restoring your iPad:

iOS: How to back up and restore your content

http://support.apple.com/kb/HT1766

iTunes: Restoring iOS software

http://support.apple.com/kb/HT1414

All the best,

Jeremy

Restoring the software on my iPad Mini helped