Microsoft recently released a new Insider Fast build for Outlook app on Windows Desktop. This new build brings inking support to Outlook. With this support, you can use your digital pen or finger to ink in your emails. Even Ink Effects like Rainbow Pen and Galaxy Pen are available.
You can insert a drawing canvas to sketch freely, or draw directly on any picture.
You can access this feature in the Draw tab that will be available on touch-enabled devices. If you are not on a touch-enabled device, you can go to Customize Ribbon and select the Draw tab.
Download this new Insider build today and give it a try.