Mistakes are common, but there are easy solutions to assist you in fixing any errors or mistakes you make while using FormSketch.
Erase / Delete:
Located in the tool menu at the top of the map, these are two options that sound the same, however while the Erase option (indicated by an eraser symbol) is more like a freeform eraser that can be used to erase any areas that you run it over, the Delete option (indicated by a bin symbol) will erase an entire selected element.
Undo / Redo:
In the top right corner of the page, there will be an Undo option (along with a Redo one, if you change your mind). This will undo the last action or edit made on the map. This is good if you have only just made the error, but if it was done before other edits have been made, then the erase or eraser options would be best to use.