How to add new values to the tax registration type LOV under customer site level

Summary:

We want to add new LOV to the customer - site - tax profile - tax registration - tax registration type

Content (please ensure you mask any confidential information):

Would like to request all your help to see if there's a lookup code to add LOV to this field?
Thanks for the help

Version (include the version you are using, if applicable):

25B

Code Snippet (add any code snippets that support your topic, if applicable):