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 Settings (click on cog icon – top right) ❯ Email ❯ Junk email and under ‘Blocked senders and domains’ click ‘+ Add’ and type or paste the copied email address or domain press Enter then click ‘Save’