Help me how do I fix this problem?

This is one of those cases where a midframe replacement is really the only solution here. Yes, you could straighten the frame, but in order to do so without risking damage to the internal components, you'll have to pretty much gut the phone anyway, so as long as you're going that far, you might as well just replace the whole thing.

Unfortunately, unlike most Android phones, replacing the midframe on an iPhone is quite literally the most difficult iPhone repair possible. Apple does not make it easy, and there are a LOT of small parts and screws to keep track of. Having authored the iPhone X Rear Case Replacement guide, I know whereof I speak. If you do want to go ahead with this, you can get a lot of tips on how to do things like removing and replacing the buttons, for instance, by reading my guide.

Of course, iFixit doesn't generally create every possible guide for every phone they support, and of course there's no guide for that replacement on your phone. However, I did located a YouTube video showing you everything involved in that repair.

iPhone 13 Centre Frame and Back Cover Replament #iphone #repair #huaqiangbei #repairshop - YouTube

If it looks daunting, believe me, it is. In order to successfully pull off that repair, you'll need to go through all of the available iPhone 13 guides to get the specifics on how to remove each part, since the video is a little short on actual instructions. Combine that with some of the details as I mentioned on my iPhone X guide, and you should be able to get through the job. Naturally, you'll want to pick up a replacement screen since you're going to have it off anyway.

Having done this job a few times on other iPhones, I do have a few pieces of advice that'll make the job easier. First of all, if you're set on buying a brand new part, look for one that advertises itself as "including small parts" In those cases, the replacement part will generally have parts pre-installed for you, often including things like the charging coil and buttons, along with seals and mesh grills. A few will even go so far as to include things like the speakers and Taptic Engine. Of course, you'll pay more for those versions, but in the long run it will save you frustration and possibly making a mistake or omitting parts. Both AliExpress and eBay have given me the best luck locating parts like that, but they're by no means the only places you can find them.

The other thing you can do is consider buying a used part. Many of them are still in perfect condition, and a lot of times they only take out the major parts like battery, motherboard, cameras, speakers and screen, leaving everything else intact. A part like that will make your work an order of magnitude easier, but takes some careful research to make sure you're getting a part in good shape that includes the parts you want. If you decide to go that route, eBay is your best bet for finding a used rear case.

One final option could be to find a fully functional phone that is iCloud locked. Swapping a few components over such as the motherboard, front sensors and front camera assembly would give you a new phone with a minimum of work.

Depending how ambitious you feel, you might consider taking lots of pictures as you work. Once you're done, you can use them to create your own iPhone 13 Rear Case Replacement guide, just as I did for the iPhone X. Naturally there were a lot of guides that iFixit didn't have, so I actually ended up authoring quite a few guides due to having to take everything out anyway.

Good luck, and be sure to come on back and let us know how it all turns out; your experience could be invaluable for the next guy who comes along with the same problem.

I completely understand being on a budget and needing to minimize the cost for this repair.

Yes, I believe the frame can be straightened out enough to be usable and allow you to replace the screen.

Based on the position of the bend, it looks to me like you can get away with removing the battery and the motherboard in order to bend the frame back into shape. These two guides show you how to take out those two parts.

iPhone 13 Battery Replacement - iFixit Repair Guide

Manuales / Apple iPhone 13 / Motherboard - Nadie Me Llama Gallina

Once you've removed those parts, you can use pliers, clamps, hammers or whatever other tools you have on hand to straighten out the bent metal. Use a straight edge like a ruler to verify that it's as flat as humanly possible in all three dimensions; once it's as close as you can get it, you should be able to reassemble your phone and be able to replace the screen with a new one.