Open the email in its own window (double click on it) then go to bottom of the email and look for the ‘unsubscribe’ link (often in small text and underlined), click on it to open the Unsubscribe webpage then confirm as required. To block an annoying email sender that does not offer this, open the email and click on the ‘More’ dots in top right. The drop down has several relevant options, just click on one – Block “name of sender” (to move it to Spam and set up a rule), Report Spam, Report Phishing and to undo, find the email in Spam and select Unblock from the More options menu