How to properly describe a business process (ddd)?

Question

Problem-Based Design

Good afternoon.
There is a business in which a user, having registered (using mail and password), can get expert advice in a certain chat. After that, he may come (or may not come) with his feet to the offices and conclude an agreement (which already includes other data - passport, etc.). The user can just as easily come to the office and conclude an agreement.
How to share it all?
User(Email email, Email password)can go to

Office (Email email, Email password, Passport: passport )

ang Get() any Services()
User is an Entity, ok. It has an identifier, it can be registered and so on. But when he comes to the office to conclude an agreement - is this another Client() entity or not? Or is it the same User just without the "passport" part? And where should the validation of this be located? in Email, Name, Passport as in Value-Object or, if these are different entities, should there be some kind of service that I access from the Value object?
sorry for the porridge