Canada is one of four countries trying out a new long-form writing feature on Twitter. The new Notes feature will allow writers on the platform to write lengthier pieces on the app. It will enable you to go beyond 280 characters using a rich-text editor for writing. A small group of writers in the country, as well as those in the US, the UK, and Ghana, are trying this feature out. But users from around the world will get to see these Notes.
Other features you can expect include photo, video, GIF, and tweet embedding, the option to edit Notes (even after being published), and a special Notes tab on the profile (first coming to the web, then on mobile). The feature is available on both mobile and the web. You can read more about the feature here.