Substring Match Tracking
I changed the color of a button on one of the inside pages and applied to the substring match across sites. I also set up a goal of tracking the clicks on the button. But I am not sure the clicks on the button are only people who landed on this specific page or any page with the change applied? If it's only tracking this specific page, is there an easy way to track the clicks site-wide?
By default click goals are tracked on every page where your experiment is running. So, if you set up a click goal on an element that exists across several pages, then it will be tracked on each of the pages where the experiment is running (ie your substring match).
If you need to modify the goal targeting, there is an area in the goal setup where you can do this easily. Check out this article for help: https://help.optimizely.com/hc/en-us/articles/200039905-Click-goals#redirect_goal_targeting