A Share Sheet is for students who have something to report to a teacher (inside or outside of the classroom). This can be used when the student does not feel comfortable verbally discussing an incident, when a student wishes to remain anonymous, or when the teacher does not have the immediate time to talk with the student. This sheet is for the student to fill out when they feel the need, and they have the ability to vent the situation and write it all down while it's fresh.
In the past, I usually had students just write on a piece of notebook paper what happened, but usually that ended up being very vague and lacked real intel, so this helped make things a little more clear. Plus, paper trails are always a great thing!