All countries supported by Stripe can be found here.
If a potential customer is located in a country not found on this list they cannot create a standard Stripe account. One alternative is to use Stripe Atlas, a product which allows users based in other countries to open Stripe accounts with US based banks.
This option does create friction, as there is a $500 setup fee, ongoing annual fees of $500+, and the potential for having to pay US corporate income tax.
An alternative is creating a custom account and working with the product team to create an integration with a payment process tool that works in their country.
NOTE: The customer cannot simply create a USD bank account to get around this issue, as Stripe requires bank accounts to be located in the country their business is located.