It can be useful to have a default and personal email signature that will be displayed at the end of all outgoing email messages.
Let’s take a look on how to add signatures in three of the very popular free email services : Gmail, Hotmail and Yahoo! Mail.
For Gmail :
From inbox, select the gear icon at top right and select “Settings”.
Under the “General” tab, scroll down to the “Signature” section, select the second radio button instead of default “No signature” and  type what is to be used as an email signature (greetings, name, contact details etc) and finally hit “Save changes”.
For Hotmail :
Go to Hotmail inbox, select “Options > More options”.
Select “Message font and signature” under the “Writing email” section. Add personal signature in the box and save changes.
For Yahoo! mail :
Go to inbox, select “Options > Mail options”.
Change the setting to either “show a plain text signature” or “Show a rich text signature” under the “Signature” section. Add the required signature and hit “Save”.
Happy emailing.