For a new company, the Cash, Check and major credit card payment methods are created automatically for you.
You may want to add a payment method for other types of payment, such as traveler's checks.
You may want to edit a payment method to change the name of a payment method you added. You cannot edit the Cash payment method.
The payment method is changed on all screens and transactions that use it.
If you delete a payment method, it is removed from the Payment Method list and from other places payment methods are listed in QuickBooks.
If you have transactions using the deleted payment method, they say "Name (deleted)" where "Name" is the name of the deleted payment method.
Often, instead of deleting a payment method, it makes sense to merge a payment method with another payment method.