Start with this website. It should help you walk thru the process of what you need to do.

Notice there is deadline of Dec 7th advertised.  This is for current Medicare users. This does not apply to persons just turning 65.  

If there are meetings put on about Medicare, I would find one and attend.  Typically, they are put on by insurance companies or insurance agents.

There is a publication Medicare and You 2026. I received a copy in the mail.  You can download a pdf here.

As far as doctors concern, you need to do your homework to make sure you can keep your current doctors.  That is a matter of decide which plan you want, and then go to that insurance company website, and if your doctors are included in that Plan. For example, my 2025 policy is thru Blue Cross.  When I looked thru 2026 Plans, some insurance company's plans did not have my current doctors.  It seems like most (all) of the Blue Cross have my current doctors. So, I have decided to stay with Blue Cross, and not switch companies.