On Mastodon, if you’re running an account that isn’t monitored by a human, it’s considered polite to mark it as a bot.
You can add the “bot” label to an account by signing in through the website and going to Edit profile > This is a bot account, then tick the box and click Save changes.
It’s not a pejorative term, it’s just used as a neutral label for accounts that post regularly but don’t have a human being replying.
Bot accounts can be very useful or entertaining, for example the How To Do Anything bot ⧉ is entirely automated but many people enjoy following it. Some bot accounts do interact, such as the Text Adventure bot ⧉, but there is no human being doing the interaction so they use a bot label.