How to remove a white line on the middle of my iPhone?

Hey there fatou130,

While service may be required for the screen, we'd like to first rule out some possible causes, along with learning more about what's happening:

1. When did this start to show?
2. If you remove any covers on the screen, does the issue remain?
3. Sometimes unexpected behavior can be resolved with a restart: Restart your iPhone
4. If you have a compatible iPad model, the latest version is iPadOS 16.4. You can verify this within Settings > General > About. In case you needed it, this link shows how to first back up, then Update your iPhone or iPad.

Cheers!