As with most things on Nostr, there's more than one way to get it done.

Primal has their new long-form composition tool that nostr:npub18ams6ewn5aj2n3wt2qawzglx9mr4nzksxhvrdc4gzrecw7n5tvjqctp424 and nostr:npub1spdnfacgsd7lk0nlqkq443tkq4jx9z6c6ksvaquuewmw7d3qltpslcq6j7 mentioned.

I am a big fan of https://habla.news/ for publishing my articles.

From there you have:

- https://highlighter.com/

- https://notestack.com/

- https://yakihonne.com/

- https://untype.app/

Heck, there's even a note taking app you can download to your desktop that can publish long-form articles to your specified relays: https://comet.md/

Or, if you are a user of Obsidian notes, there is a plugin for publishing them to Nostr as long-form articles.