Memo emoji is the picture of a sheet of paper with the text on it — it is meant for public speeches in order not to forget anything important. It may be used exactly in this meaning, as well as in the context of education (especially, writing essays and so on), office work (with 📁 File Folder emoji or others), or writing some piece of literature as a hobby or professionally.
Examples of using
“Let’s see what else is on my checklist 📝”
“I’ve almost finished my report 📝”