Preferably without changing the source code of erpnext, this was easily achievable in erpnext v12 by adding an item of type Link in dekstop.py’s json, but there’s no such thing in erpnextv13
By “external link” I mean an icon on the side menu or a shortcut on the dashboard that takes you to another website. ie. https://www.google.com when you click on it. A simple hyperlink functionality.