You can edit a credit class to change its name or what its credit can be spent on. Changes to a credit class also apply to credit customers already have in that credit class.
Before you start
Think about the customers who already hold credit in the credit class. Whatever you change applies to their existing credit straight away.
Steps
Go to Settings > Loyalty & Credit.
In the Credit Classes table, select Edit next to the credit class you want to change.
Change the Name if needed.
Tick anything the credit should now be spendable on, and untick anything it shouldn't: Wine, Cider, Beer, Spirits, Other products, Shipping, Club runs, Gift cards and Excluded products.
Select Save.
What happens next
The change applies to all credit in the credit class, including credit customers already have. For example, a customer has $100 of credit in a credit class with only Wine ticked. You edit the credit class and tick Shipping. The customer can now spend the $100 on the shipping part of an order as well as on wine.
Troubleshooting
I can't edit a credit class I deleted. A deleted credit class can't be edited. Customers keep the credit they already have in it. See How to delete a credit class.