@Yaujj75 If your wiki uses talk pages, and you want to automatically leave welcome messages on those talk pages, you have to write a script that uses the MediaWiki API. Fortunately, this API is very well-documented. You just have to find an appropriate API call to gather a list of users to leave messages for (GET), and then (for each user), make a separate API call to actually leave those messages if they're new (POST).
If your wiki uses message walls and you want to automatically leave welcome messages on those message walls, you have to use the Discussions/Nirvana API. This API is not well-documented, but I've written some personal documentation which you can see here: User:Atvelonis/Bot/Discussions API. You'd probably use the same GET/POST structure as before.
If you want to run such a script fully automatically, you need to set up a recurring task with Windows Task Scheduler or Cron.
You could use the Discussions API for this if your wiki uses Message Walls, yes. I haven't tried, but it wouldn't be that difficult. Maybe I can add a use-case for that in my documentation if I have time (my list of controllers and methods is not complete).
I would also clarify that a server is just a computer that runs 24/7. If you really want, you can use your personal desktop computer for this. If you're on Windows, there is a built-in app called Task Scheduler that lets you run scripts on repeat. There are similar tools out there for Linux and other operating systems as well.
example.fandom.com
under "Custom" (instead of "Wikia") in Options -> Preferences -> Site, when you tell it where to look.
</p>