Microsoft Whiteboard is a free-form, digital canvas where people, content, and ideas come together. You can use Whiteboard to collaborate with other people and accomplish many activities, from brainstorming and planning to learning and workshops. 

https://youtu.be/YBnojDFXo4k

Advantages

• Free to use if Microsoft account is available. 
• Automatic save option.

Disadvantages

• Students must log in with a Microsoft account.

Manual? Please follow this link.