How do I fix the front passenger side panel of my car?

Most likely that portion was glued on and has just come loose. What I would do is remove the door panel and just find out if there are screws or bolts that hold that handle on. More then likely there will be two but I doubt they will tighten enough to remove that.

https://www.2carpros.com/articles/door-panel-removal

If it does not then I would put some sort of glue or adhesive in there and push that portion back in place. Then set something up so that it stays in place until it dries. Otherwise, you would need to replace the door panel or handle if they are available.

Thanks for the pictures that really does help. Let me know if you have questions on this and we can go from there.

I would find something that is large enough to push down into the opening of the handle so that it puts pressure against the panel and closes that gap.

You will want to use something a little stronger then super glue. Something like a two part epoxy would be best. Just go to the parts store and see what they have to offer that is good between 0 degrees up to 200 degrees and you will be fine.

Just tape off the door panel and handle so that when you put whatever you are going to use does not get on the visible part of the handle and door.

I think the issue is you are trying to adhere it to fabric. That does not make a good mating surface. However, I would try this stuff. It is not specific for fabric but they use this for making handle material on custom knives and most of the time they are some sort of fabric or natural material.

If this doesn't work, then it is warped so bad that it will not hold.

I was thinking about that but I am not sure it will hold to the fabric either. That is why I was thinking a liquid/epoxy would be better. However, it can't hurt in trying but you are only going to get to use one because once one is in there, I doubt the other would work either.

You know what they say, if you can't fix it, JB Weld it.

I would wedge something in the door handle to force this part of it down.

Take a look at the picture.

I would just use a piece of wood so that you can cut it to the length you need to get the panel flush. Just test it before you put the adhesive in there. If you need to make it wider to just to make sure the hole thing is flat against the door panel.

Haha, I understand. Unfortunately that is probably the best option with this type of issue. These types of things were not made to be "repaired" so replacing them is really the best and only option. Sorry it didn't work out. Thanks for using 2CarPros and please come back in the future if you need more help with other things. Thanks