Agree on a small support task first
A trusted helper might need to see a player error or point out a setting without operating the computer. Microsoft describes annotation and viewing tools as well as full control. Before connecting, close private messages and account pages that are unrelated to the problem. Use a session you arranged with a known person or support route, rather than trusting an unsolicited caller simply because they can supply a code.
Read each permission as it appears
Microsoft’s Windows instructions have the person receiving help enter the assistant’s code and allow screen sharing. A later full-control request is a separate decision. You can decline it and continue with instructions where practical. If you do allow control, Cancel control stops that permission; Leave ends the session when the task is finished. A code identifies the connection being joined, not the helper’s business identity.
Keep account entry under your own control
For a viewing problem, show the error and relevant settings while keeping playlist credentials and personal messages out of the session. If an application asks for an administrative permission, pause and understand the requested change before responding. Microsoft’s technical documentation notes that some prompts need the sharer’s response. Finish by leaving the session and checking the actual player behaviour yourself. A successful connection alone does not establish that an account, payment or stream has been repaired.
Questions, answered
Does allowing the screen immediately give the helper full control?
The documented Windows flow makes full control a further request that the person receiving help can allow or deny.