Evernote is an email client that allows users to forward their unwanted or non-essential emails to it, which then stores them in a designated notebook for later reference. This can be done by forwarding emails to Evernote's unique address, which is found through the application's settings page. Alternatively, Zapier can be used to connect an email app to Evernote and automate workflows that send certain emails or labels to the service. By using either method, users can declutter their inboxes while still having access to valuable information stored in Evernote.