A set of frequently used tasks is built into Azure Pipelines; however, there are even more available using the Visual Studio marketplace for Azure DevOps. If you are an administrator, you can find and install extensions that add tasks here. If you are a regular user, you can find tasks here as well; however, you cannot install them, only request them. Your Azure DevOps administrator will then be notified and can install the extension on your behalf if they approve.

Of course, you can write and distribute extensions with tasks of your own as well.