Paypal is usually the most common option for artists
There are others that use CashApp, Stripe or other similar methods that are virtual wallets.
There are artists that only work with local folk so then they use bank transactions and similar.
Still, I believe that knowing the country you're from may help some a bit, be it if they are from the same country or if there is actually an alternative for Paypal.
Still, I would recommend to be careful, since nowadays when people say "someone approaching me for commissions through instagram" or similar, is highly likely it was a scam attempt, these are becoming extremely common and they usually try to go for people who are new to commissions or artists in general. A lot of genuine people interested in commissions would try to dig up through your profile to know if you take those kinda gigs, and would likely not ask if they see you never stated such thing.