Go search on the web for “Merchant Payment Processing”. You’ll find tons of sites that do this and you can research and compare to find the one that suits your needs.

If you want to use PayPal, you must contact them and ask them how to set up an account, and how to set up to accept paypal payments.

If you wish to accept credit card payments, first you have to contact the credit card companies and make arrangements with THEM. They have a “floor rate” which is a % they keep of what they collect for you.