Look for 'subscription form' or 'subscription widget' or even 'lead capture'<p><a href="https://documentation.mailjet.com/hc/en-us/articles/360042502194-Subscription-Widget" rel="nofollow">https://documentation.mailjet.com/hc/en-us/articles/36004250...</a><p><a href="https://sendgrid.com/blog/building-a-sendgrid-subscription-widget/" rel="nofollow">https://sendgrid.com/blog/building-a-sendgrid-subscription-w...</a><p><a href="https://gleam.io/app/capture/mailjet" rel="nofollow">https://gleam.io/app/capture/mailjet</a><p>The email addresses end up in their database but you can download the list there. They make money from people sending regular newsletters, that's optional though.