The drawing tool is a feature that can be included in a Form. It can only currently be accessed when filling out the Form through the Formitize App.
To add the drawing tool to a Form, you are able to drag and drop the tool from the Toolbox in the Advanced section in the Form Builder. When you click on the FormSketch field in the form, you will see further options that you can change in the Field Settings in order to set up your Drawing tool for use.
The Background dropdown options allows you to select an image from your Resources, that you can use as the background of the Drawing Tool. The Legend options will allow you to add icons to your Drawing tool for you to use as well. See the links below for more information about uploading Legend icons / symbols.
Once this has been all set up, then you can Save the form and then Deploy / Publish Template to ensure the changes have been saved.