test.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Test</title>
  </head>
  <body>
    <button onclick="sendTest()">Enviar Mail</button>

    <script>
      const sendTest = () => {
        const response = fetch(
          "https://enerjet.com.pe/mail/api/gardi/bienvenida",
          {
            method: "POST",
            headers:{
                'Content-Type': 'application/json',
                'Authorization': 'Bearer ' + ('BEREAR_TOKEN xxxxxxxxxxxxxxxxxxx')
            },
            body: JSON.stringify({
              name: "Koki",
              email: "christianchangh@gmail.com",
            }),
          }
        );

        return response;
      };
    </script>
  </body>
</html>