SMTP (Simple Mail Transfer Protocol)
SMTP is the industry standard protocol for sending email. If you’re looking to send email, then you’ll use SMTP instead of IMAP. An SMTP relay service can help you send email without having to build your own SMTP server.
IMAP (Internet Access Message Protocol)
IMAP is one of the most common protocols for receiving email. IMAP syncs messages across all devices.
POP (Post Office Protocol)
POP3 is another protocol for receiving email on a single device. Using POP3 means that your email will be accessible offline and deleted from the server.
AOL
Gmail
Hotmail
Outlook/Outlook Express
Yahoo! Mail
The use of a plus sign ("+") in an email address can be very useful. Gmail, as well as two common mail server systems, sendmail and CommuniGate Pro, will deliver mail addressed to "user+tag@domain.dom" as though it were addressed to "user@domain.dom". The "+tag" portion of the email address can then be used both for filing mail and for screening it.
Some apps and devices use less secure sign-in technology, which makes your account vulnerable. You can turn off access for these apps, which we recommend, or turn it on if you want to use them despite the risks. Google will automatically turn this setting OFF if it’s not being used.