The joyous thing about working as an adjunct faculty member at numerous institutions is sifting through the bureaucracy, or as I like to call it, bureaucrazy - because it is poorly designed and makes you crazy.
To access an ID number, at George Washington University, one site says
"Go to this URL and enter this personal information."
Once at that URL and after entering that personal information, the response received is
"We no longer accept your personalized information. Please enter your ID number."
There is a number to call for help. At that number, callers are directed to call another number. The second phone number leads to an answering machine that repeats the information found on the URL.
At an institution where the incoming freshman class is paying $50,000/yr, one might hope they had this sorted out. Apparently Major Major is a live and well and working at GW. You can make an appointment to see him when he's not in.