GMerge is a Chrome extension developed by Social Analyzer that allows users to send bulk emails from Google Sheets or previous campaigns in Gmail. With just a few simple steps, users can easily send emails to multiple recipients at the same time.

To get started, users need to enable the extension and click the "COMPOSE" button to open a New Message popup. From there, they can enter the recipients' email addresses and click the "GMerge" button to choose a list source. The extension will automatically fill in the mass mail accounts in the recipients' input field. Users can then write the subject and content of the email and click the "GMerge" button to send a batch of emails quickly.

GMerge also offers the option to import Gmail accounts from Google Sheets. Users need to sign up with Google to authorize GMerge to access their Google Sheets. The sheet must have at least one column with email addresses.

It's important to note that GMerge is a third-party extension and is not developed by Gmail Inc.