You have to be signed into your Yahoo! Mail account, in order to be in a position to read the emails in your inbox, send emai ... ls to your contacts, check if you have new mails or do anything else with the account. Thankfully, the Yahoo Mail sign in procedure is very simple. It is really a question of entering your Yahoo Mail username, and your Yahoo Mail password into the appropriate boxes, and then clicking on a button labeled ‘sign in.’ read more