By default, the platform does not have this option. You can use the following JavaScript code to change the URL of the Sign Up button.
Please follow the steps below:
1. Go to BuddyBoss > Theme Options.
2. Under Custom Codes, enable JavaScript.
3. Append the following:
jQuery( document ).ready( function() { jQuery(".bb-header-buttons > .button.signup").attr("href", "https://LINK.HERE/") });
4. Click Save Changes.
Screenshots
Without code
With code