You can sync your mail with your devices and other email accounts. Follow the procedure that is mentioned below to sync your mail successfully from email setup center.
Open the Gmail app on your device and tap the menu icon available on the top-left corner of the screen.Select the Settings option and check if the Sync Gmail option is checked. If not, highlight the box. You have now turned on mail sync on your device.
Syncing your Email constantly will lead to more data usage. You can set the email syncing frequency according to your choice in many of the mail apps. There are inbuilt durations in the app, and it will sync the mail based on the time period you have specified. Instructions are given from the email setup center.