Please note that the accepted credit cards can (usually) not be defined in ConfTool, but the supported cards are defined by your acquirer contract or the payment service provider being used.
The text shown in ConfTool is for information purposes only and should match the options offered by your acquirer/payment provider.
From our experience all payment providers support Visa and Mastercard as a standard.
Many acquirers require a supplement contract for American Express, JBC, Discover etc.
Please note PayPal supports Visa and Mastercard for clients/participants from all regions, but more cards are supported depending on the country of the client and the merchant (for example American Express and Discover are available to clients from US, "Laser" to Irish clients, "Maestro Card" to clients from Austria etc.).
For Stripe the supported cards also seem to depend on the region, but usually all major cards like Visa, Mastercard and American Express are supported.
If you want to change the cards listed in ConfTool for your gateway system, please proceed here (see screenshot):
Overview => Settings => Manage Payment Options
The wordings for PayPal and Stripe payments can also be found in:
"Settings => Wordings and Phrases"
For instance search for "PayPal" or "Stripe" and "Mastercard".
In most cases, the default wording will be fine.