Draw My Life is a video made by popular YouTubers where they explain their past lives and how they became popular. Several examples of people who have done DML's are Anthony Padilla, Felix Kjellberg, Lia Marie Johnson, etc. These are mostly made so you can understand what has happened before, and so people who hate said YouTuber will feel a little empathy.
The origin is unknown, but was most likely started by a group of major YouTubers who got extremely bored.
How to make a DML
All you need is an overhead camera, a whiteboard, and marker(s). Then when you finish, speed up the footage, mute the video, and add your own commentary.
Ashens made a parody DML.