Screen is showing vertical lines and image is duplicating on screen

@vibhor30564 we really would need to see what this all looks like. Post some good pictures of that with your Question.

It is possible that this is a bad display. It can also be a bad connector (check for corrosion, broken and bend pins) Finally, it is possible (unlikely) that this is an issue with the circuit board. Start with a new display.

Since iFixit does not yet have a guide for this, use the one from here Replacements are readily available at plenty of online stores.

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 the same problem 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!