An incognito (or private) window in a browser can help you troubleshoot issues you may be having with a particular website or service. It does this by giving you a temporary "clean slate" browsing window that doesn't have cookies and other detritus from your previous browsing sessions.
Note that closing a private/incognito window deletes all your browsing history from that window, so close with caution. (It wont' affect your main browsing history or cookies.)
Here's how to access a private or incognito window in the big three browsers.
Chrome:
Edge:
Safari:
