There are a few ways that you can start a newsletter on a blog. One way is to use an email subscription service such as MailChimp or Constant Contact. You can also create an email subscription form on your blog and then send out newsletters automatically using a third-party email marketing service. Another way to start a newsletter is to create a blog post and then include a link to a form that people can use to subscribe to your newsletter.
You can also create an email list using a third-party tool, or you can manually add subscribers by inviting people to sign up through your blog. Once you have created your newsletter, it is important to promote it and make sure people know about it. You can do this by placing links to the newsletter in your posts, including in the comments section of your blog posts, and by promoting it on social media platforms such as Twitter and Facebook. Finally, it is important to track the success of your newsletter campaign so that you can optimize it for future iterations.