Short answer: No, you don’t need to make an account to request a commission from an artist on VGen.
Right now, clients are actually not able to make accounts on VGen at all.
Client accounts are coming in the near future to enable clients to keep track of ongoing and past commissions, get comm / waitlist opening notifications, and more.
Even once client accounts are live, clients will always have the option to make requests as a guest (without making an account) - although guest account features will be limited.