Hello Kathryn, and thank you for choosing JUSTANSWER.com
iPads do NOT always have the same iOS and RF Hardware as cell phones do, so just because it works on a Apple iPhone, does not automatically mean it will work on an iPad.
So, what exactly do you mean the iPad wont recognize credit card readers? Do you mean, you want to make a PURCHASE with your iPad, but the credit card reader wont connect to the iPad for processing. Apple calls it APPLE PAY, and Samsung calls theirs SAMSUNG PAY.
The reason is....iPads do NOT have the NFC (near field communications) hardware that allow for you to TAP on the credit card reader and the payment to go through.
Is that what you meant?
check the location settings. card readers usually require that you have those on
you also need to check the blue tooth as most card readers actually connect via blue tooth even though they plug into the device.