Outlook 365 for Windows now lets you draw into emails. It’s an extension of the existing drawing features in Word, Excel and PowerPoint for Office 365 customers.
According to Microsoft, from Office 365 version 1906, build 11727.20210 Outlook’s message ribbon should have a Draw tab.
The Draw tab should appear if your computer is touch/draw enabled. If not, check the Customize Ribbon dialog to enable the Draw tab.
Drawing is available over pictures or in a drawing layer. Obviously not possible in plain text emails.
This is different from the Ink or Ink to Text feature available at Message | Review | Start Inking.