How to get Backup of the Gmail tool?

Afraid this doesn't seem to be something you'd really use Jamf for. Are you talking about a single account, or trying to back up a full enterprise/company's data?

There are a few ways to back up Gmail if you want to. You can download your data using the Google Takeout service, but it can take a long time, and the files sometimes come in big formats that aren't necessarily easy to get to right away.

You can also set up Gmail with an email client like Outlook or Thunderbird and then export your data from there. This works, but you have to set it up by hand and configure IMAP, and it doesn't always work if you need backups on a regular basis or at a predetermined time.

There are special solutions that can help people who require a more dependable and easy way to back up Gmail data in a variety of formats, such as PST, MBOX, EML, and others. For instance, I've seen people use special Gmail Backup Software that makes it easier to save emails to their own computers or to external drives. This software normally lets you choose which emails to back up, set a schedule, and choose from a number of output possibilities. These kinds of tools are far more useful if you don't want to have to do the same thing by hand over and over again.

You just asked a question but did not present a problem. What is the problem you are trying to solve?

Data backup is well out of the domain of MDM, google themselves may have some tools but without knowing more about what you are doing and why I cant really suggest anything.