Adding a New User

Hello All, 

Technical question and I appreciate your help!

user from organization A has pro license and he wants to to publish reports to organization B. Can you confirm if these are the only options to do that:

1-organization A shares the actual pbix file with organization B and organization B publish it to their server.

2-organization B creates a new user account and link it to their subscription that would allow the user from organization A to create and publish the report.

also another question, can organization B allow the user using his organization A account to publish reports to their server?

Thanks again!