Xournal lets you paint on a document, which I guess isn’t what they need when they talk about legal stuff. Digitally signing a document is still one of the rare cases where I boot up my windows vm. It’s so annoying that there’s practically no way to do that in Linux as my company’s processes rely on it.

Then you’re working with the wrong others.

If you host a forum, you can easily access the database to move threads into some kind of archive if you no longer want to host it. It could also be moved to another server. Stuff like that.

Using a proprietary service instead is just a bad idea.