How to remove the line in the middle of the screen

@shidadmixed6916 without seeing hat you see and only going by your description, it sounds like a bad screen. The only way to fix that is by replacing it. Since iFixit does not yet a specific guide for this, use the one from here Replacement screens are readily available at many online stores. Just make sure you get the right one for your exact model.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!