If I want to know anything about anyone on VATSIM I can look up the CID in the stats page or I can look up the CID via the direct feed.
For example, if I look myself up I would go to https://api.vatsim.net/api/ratings/1289149/ and I would get back
id: "1289149"
rating: 10
pilotrating: 0
militaryrating: 0
susp_date: null
reg_date: "2014-04-22T20:09:18"
region: "AMAS"
division: "CAR"
subdivision: "SDO"
lastratingchange: "2021-04-06T23:12:47"
In reality, VATSIM also stores more data that can be pulled and validated via the API. It also includes:
VATSIM Registered Email
VATSIM Registered First Name
VATSIM Registered Last Name
VATSIM Registered Country Code
VATSIM Registered Country Name
With the exception of Hub selection, The pilot would not need to add anything. All the relevant data would be pulled through the API.