Login-PopUp | Reusable Pop Up View for Sign up or Sign | Authentication library

Without seeing all the code it is difficult to see if modifying these files would affect other spots of your site.

Your "header-logo.php" file is checking to see if you uploaded a custom logo and setting the values to display the logo, alt tag and description. If you are able to find where you upload your logo you could swap it there (but it would be for all logo uses in your site).

If you want the logo changed only in this specific location, you could simply hard code the image of choice as follows:

The button you are looking for is inside iframe so first you have to switch into that iframe
You are using a wrong locators.
Use //button[@data-qaid='signInOneConnect'] xpath instead.
Additionally, you are talking about the https://playwsop.com/play page and not https://playwsop.com/

Neither, at least not directly.

The HTML you have will trigger a GET request. It can't do anything else.

It will be some client-side JS that is searching the document for elements which are members of one or more of those classes and adding an event listener that prevents the default behaviour of the link and makes a POST request.

Your server configuration can't influence it either. While it could issue a redirect response there is no way for one of those to response to a GET request in a way that causes the browser to make a POST request (although the reverse is not true).