If you want to add a bot to a Discord server, you must be an administrator of that server. Users with permissions less than administrator won’t be able to add bots to the server.

How to add a bot to Discord. You can add a number of popular, premade bots to your server. One of the most popular is MEE6. Check permissions. You must be an administrator on a Discord server or ...

As Discord itself says, until now bots are something the platform has supported, “but not properly embraced,” and now it plans to build features specifically for bots.