I have uneven teeth. One tooth is shorter than the other! How to fix this?

From your description, it seems as though the implant crown is the only problem.  You can have this issue fixed by having a new crown placed that is the same shape and height as your natural teeth.  If your problem is with the implant placement, you will need to discuss this with an experienced periodontist.

its not an issue. tell yr implant dentist to re do that crown. also if u want  to improve esthetic, go for zirconia abutment.

It depends on how you define "easy".  The only way to properly fix the length of the tooth is to redo it. This is not difficult but will take some time.  Good luck!

yes, it can be done changing the abutment,and making a more aesthetical profile, and just in case you have the implant not set in proper height, that would be a different solution, that you will need to discuss with your doctor. the abutments and crowns that go on top of an implant can be done in zirconium, to make much better layout.