Ted here from Shopify! Thanks for reaching out to us. :-)
The POS app will only show a credit card gateway option if it's connected with Shopify Payments. So, to place a test order, I'd recommend following the below steps.
In addition to the above, I'd also recommend taking a look at this guide for a full list of payment options available within the POS checkout.
If there is anything else I can help you with, please let me know, I'm happy to help!
Thanks a mill!