Clients management

My site is only logged in by the seller (service provider), who needs to register clients and manage it (e.g. send them a payment request). I am not sure how to achieve that. would love some guidance.

Wix Editor

What are you trying to achieve:
Trying to understand how the seller/service provider can manage his/her clients with wix. I need:
Understand how the seller can add a client and where/how it will be managed.

Thanks in advance.