I discovered the Seesaw app, which allows students to create drawings, videos, and pictures that become part of an online portfolio. Although it is not THE answer to assessment, it has become one of my (and my students’) favorites.
"The Seesaw app: Providing differentiated assessment opportunities,"
Colorado Mathematics Teacher: Vol. 50:
3, Article 2.
Available at: https://digscholarship.unco.edu/cmt/vol50/iss3/2