Hello alex_marie10,
Welcome to Apple Support Communities! I understand that you're encountering white lines over the number and emoji symbol on your iPhone 11 Pro keyboard. I appreciate you including a screenshot of that behavior and would be happy to help.
Try restarting your iPhone first, then see if you can replicate the issue:
Restart your iPhone
If the lines reappear after a restart, do they only show when your keyboard is visible or do you see them on other apps and screens as well? If it only occurs when using the keyboard, I'd like to have you switch to another keyboard, then check if the lines still appear:
About the keyboards settings on your iPhone, iPad, and iPod touch - Apple Support
Keep us posted on the results.
Cheers!