How to renew AppleCare+ for iPhone?

For information about how to extend your AppleCare+ coverage, read this support article “Get new AppleCare coverage after your AppleCare plan expires” --> Get AppleCare coverage for your Apple device - Apple Support

miiguelkf wrote:

I have an iPhone with an active 2-year AppleCare+ plan.

It is going to expire in November, but I want to renew it, either with another yearly plan or a monthly one.

I can't find a way to do it, though. Does anyone know how?

Once the plan expires, you will be given 45 days to renew it (30 days in Mainland China), which is usually on a month to month basis. The offer to extend it, however, doesn't happen until after the plan expires.