Some of Fandom's features can be enabled by using Wiki Features on your wiki. This is only available to a wiki's admins.
To find this page, click on "admin" on your bottom toolbar - that will take you to the Admin Dashboard. Find "Wiki Features" in the top row of icons on that page, and you will be taken to a page where you can select features such as chat.
To request an interlanguage link please see this page on Community Central.
For other features and extensions you will need to contact us, such as for: