Ko-fi does not process payments or take a cut of transactions. Supporters pay Creators directly using PayPal or Stripe (Stripe is only available to Ko-fi Gold members). To use Ko-fi all you need is the email address associated with your PayPal account.
When creating an account on Ko-fi you will be asked to enter your PayPal account email and preferred currency. You can still sign up to Ko-fi if you don't have a PayPal account yet, but you won't be able to send or receive Coffees or Commissions until you have one. You can change your PayPal email anytime from your Payment Settings.
Tip: Make sure your have clicked your verification email from PayPal or your payments will have a 'Pending' status until you have verified the email.