Risa, sorry for the delay with the answer. As far as I can see, you operate with X-Cart 4.0.19 and X-Payments 1.0.6, the credit card form is displayed on the separate page. There are two points of modifying the interface of the credit card submit form.
The first points is the credit card form itself, i.e. the text fields for card number, cardholder name, expiration date etc. You cannot change the content of this form, it's displayed via the X-Payments core. However, you can change its appearance with the help of the corresponding CSS file. The CSS file is located in the <xp-dir>/public/templates/
directory, its name matches the name of the template: default.css
The second point is the layout of the page. It's contained in the HTML files in the <xp-dir>/lib/XPay/Templates
directory. You can modify these files so that the "separate" page looks like your store, e.g. add logo, header and footer. Make sure that all the content images are loaded by HTTPS protocol (i.e. images URL's start with https://)
to prevent the warnings of insecure content.
The credit card form in these files is replaced with the <template/>
tag. When the page is displayed the form is substituted instead of this tag, so you should not remove it.
* * *
And to answer your questions.
1. the page that briefly appears AFTER you choose the payment method but BEFORE you get the the cc entry page.
This page is displayed by the store, not X-Payments. By default the code which displays that "brief" page is in the <xc-dir>/payment/cc_xpc.php
2. the page that appears after you enter the cc info and it says, "Order Processing."
As far as I can understand, you mean the "The payment is complete. Returning to the store..."
text. It's displayed by X-Payments, you can change its appearance via CSS file corresponding to the template (in the same way as the credit card form). And the same way for the "Payment is being processed. Please wait..." block which is displayed on the top of the page right after the credit card is submitted and the page is faded out.
P.S. Make sure you approve any changes in the X-Payments template files! X-Payments has an internal protection which doesn't allow process payments until the changes are approved by the admin.