What is the process of registering my own extension?

There are some of the patient data which will not fit into
the patient resource so I go for extension. After writing the structure
definition manually where do I need to register it ? Do I need to register in
the HL7 registry or in the project domain or in the GIT ? after registering the
structure definition I will include the URL in my extension how do I know that
extension is adhering to the structure definition from the registered URL.

.I’m stuck here.can someone please help me!!!

There’s no requirement to “register” extensions, only a requirement that they be available to any system you send an instance containing the extension to. The easiest way to do this is to have the URL for the extension resolve to the extension definition by hosting it on a website. Alternatively, you can put it in a public registry such as the Furore Simplifier.net repository. HL7 is working towards standing up an “official” registry implementers can use if they wish, but it isn’t available yet.

thank you for the information:)