How to extend my iPhone coverage?

If you are referring to the standard one year warranty which came on your iPhone, you cannot update the coverage at all. If you purchased an AppleCare+ Plan within 60 days of purchasing your phone, in some areas, you can extend that coverage within 30 days of the plan expiration. If you didn't buy the coverage, or you didn't extend the coverage if you did within 30 days (where eligible), you cannot extend the coverage.

If your phone needs repair, you will need to cover the repair costs. At a minimum, you can schedule an appointment at your Apple Store Genius Bar for evaluation and options.

I want to delete my coverage