How to make a PC accessible from the Internet by name?

Question

Network administration

Good evening!
The bottom line is, there is a PC with a direct connection to the Internet, IP white. It is necessary for this (through this) PC to obtain a Let's Encrypt certificate, and for this you must specify a domain name. The first question is how to bind the name to my ip? Where and how to register, if necessary.
It is highly desirable for free.
What else, this PC will be used to connect users from the Internet, phones by DNS name.
Can anyone suggest what needs to be done?

Answer 1

You buy a domain name from any registrar and bind it to a white IP.
On the router that gives the Internet to the PC, forward ports 80 and 443, in theory, this is enough (for other services, forward the corresponding ports).