I want to add an additional button called "Configure another service" along with already existing buttons "Save Configuration" and "I'll do this later" in a configuration pop up window for Google/ Github OAuth providers in meteor.
Which file or service-configuration parameter or file can be changed for the above layout of the file?
To change the content of the popups, you need to modify the HTML template that generates the popup.
In this case, the template is called _configureLoginServiceDialog, and it is found in the file login_buttons_dialogs.html
of the accounts-ui-unstyled package. accounts-ui-unstyled gets added as a dependency when you add any of the accounts-ui package variants.
But since the template is in a package, you cannot modify it directly.
What you have to do is create your own version of the accounts-ui-unstyled package (The original is here: https://github.com/meteor/meteor/tree/devel/packages/accounts-ui-unstyled) in your project, then meteor remove accounts-ui-unstyled, and meteor add my-own:accounts-ui-unstyled.