This gist is part of a blog post about mail merge script for Gmail - https://mailmeteor.com/mail-merge-gmail/script

mail-merge-gmail-script.js

function sendEmails() {
  const recipients = ["sally@mailmeteor.com", "neil@mailmeteor.com"];

  const template = {
    "subject": "My mail merge script for Gmail",
    "content": `Hi,<br><br>
    
    I just wanted to show you how to send emails in bulk with my Gmail account!<br><br>
    
    Take care,<br>
    - Corentin<br><br>
    
    PS: <a href="https://mailmeteor.com/mail-merge-gmail/script">Click here to do it by yourself</a>`
  }

  recipients.forEach(function (recipient) {
    MailApp.sendEmail({
      to: recipient,
      subject: template.subject,
      htmlBody: template.content
    })
  })
}