Existing users can’t invite anyone to your product for Require admin approval option

[YY Brother]

for Existing user permission: Require admin approval

A: Existing users can’t invite anyone to your product, regardless of your approved domain settings.

=> How to replicate it?

B: Anyone can still request access to your product for themselves or on behalf of someone else. An organization admin needs to approve the request.

=> What's the relationship or difference between  & B in case of no approved domains set for my site?

Refer to: https://support.atlassian.com/user-management/docs/control-how-users-get-access-to-products/