Gmail adds 'undo send' feature officially, letting people take back their embarrassing emails Gmail newest addition is an �undo send� feature, which lets people recall emails that have been sent, up to 30 seconds after they�ve been despatched. It works by holding back the email for a pre-defined time, and then letting it go if users don�t say that they�ve sent it in error.Users must enable the feature through the settings page in Gmail, by clicking in the cog at the top right hand screen and scrolling through the general tab. It also gives the option to choose how long the undo send feature shows for � offering settings between 5 and 30 seconds.The feature is also available on Inbox, Google's special mobile app that organises emails and aims to make them easier to read.The company has long offered the feature as part of its Labs, which gives Gmail users special features that can�t usually be accessed, before moving them to the main product if they�re successful. Other features currently being experimented with are options to use canned responses to emails so that they don�t have to be typed out every time, and a little icon that shows official messages are really coming from where they�re supposed to be.