You can change your status to Automatic, Do not disturb, or Away.

Change your status on Gmail

  1. Open Gmail.
  2. On the top left, tap Menu Menu .
  3. From your status indicator, tap  Down .
  4. Choose how long you want to mute your notifications and appear as "Do not disturb." 
Tip: When your status is on "Automatic" mode, you'll be shown as "Active."  If you're inactive for more than 15 minutes, your status will switch to "Away." 

Understand Gmail status

Status icon Status text Status meaning
Green Active You currently have Chat open.
Red Do not disturb Mute is turned on or user is presenting during a meeting.
White Away You aren't connected to the internet or haven't interacted on Chat for more than 15 minutes.
 

For more information please click the following link:  https://support.google.com/mail/answer/9916566?hl=en&ref_topic=3394219