How do I get paid using Apple Pay

Unless you, as the service provider, are equipped to accept Apple Pay payments you can’t. For that you will need a payments processing service that supports Apple Pay. For example Square is one such payments processing that small merchants use.

Your client can also pay you using Apple Cash or other funds transfer apps (think Venmo or PayPal)

Send and receive money with Apple Cash - Apple Support

You don't, unless you are a merchant with a POS device that supports Apple Pay.

Again, you cannot. The only way to get paid is via Apple Cash which is only available in the USA.

You don’t. What sort of “payment” are referring to? Does someone want to send you money? Are you referring to Daily Cashback rewards on an Apple Credit card?

Someone wants to pay me for a service by using Apple Pay. How do I receive this payment?

It’s one time payment for a service