I’ve been meaning to look into webmentions for a while now. I set up a protonmail account and linked it to the site so I could use IndieLogin. I included a hidden link to the email on my homepage.
<link href="mailto:firstname.lastname@example.org" rel="me">
From there, I can now use my site to sign in at webmention.io. I add the following link references to pages that I want to accept webmentions for:
<link rel="webmention" href="https://webmention.io/username/webmention" /> <link rel="pingback" href="https://webmention.io/username/xmlrpc" />
Max Böck has a helpful article on webmention implemenation for static sites and he suggests using webmention.app to send them.