Depends upon the client and the kinds.

Each note/event you send is actually a little json file and the part you can see in your client is the part written under the "content" header. Another part is the "kind" section.

If you want to write and read from this relay, you need to go to a client that uses these kinds of events and add it to the relay list in the settings.

Some clients that read and/or write such documents (like long-form articles) are Coracle, Amethyst, Habla, Highlighter, Nostrudel, Freerse, GitWorshop, Wikinostr.