There are two ways your devices and clients can communicate with Gmail:
A one-way communication path (POP). Your device asks us for data and pulls it from our servers — but that’s it. Things you do on your device have no effect on the server. If you read a message on your phone, then log in to Gmail, you will see that same message marked as unread. It may start to feel like Groundhog Day.
A two-way communication path (IMAP). Unlike with POP, your devices talk back to our servers and sync your changes automatically with IMAP. When you sign in to your Gmail account in a web browser, actions you’ve taken on your email client or mobile device (like putting a message in a ‘work’ folder) will also appear in Gmail (your message will already have a ‘work’ label on it). This all happens automatically once you set up IMAP, so you don’t have to read or sort all your mail twice. This is really helpful when accessing Gmail from multiple devices.
You can retrieve your Gmail messages with a client or device that supports IMAP, like Microsoft Outlook or Apple Mail.
To enable IMAP in Gmail:
Sign in to Gmail.
Click Settings at the top of any Gmail page.
Click Forwarding and POP/IMAP.
Select Enable IMAP.
Configure your IMAP client and click Save Changes.
Supported IMAP client list
Once you’ve enabled IMAP in Gmail, just configure your mail client or wireless device to download Gmail messages. To learn about configuration settings, click the name of your mail client or wireless device below.