You can attach any files related to your project to a task — documents, images, videos, links, materials etc.
If you are used to storing files in cloud storage such as Google Drive or Dropbox, you can attach links to them to a task. This way you will have all your documents in one place, and you can quickly find all the task details.
There are no limits on the number of attachments, only on individual file size. It varies from 5Mb to 100Mb depending on your subscription type.