How do I indicate that I've written my letters?

Log in to your Vote Forward account and go to your dashboard. You can mark all of your letters "prepared" by clicking the gray right-facing arrow button. This will move your bundle into the "Prepared" column. 

To mark individual letters within bundles as "prepared," click on the down-facing blue arrow button next to "View 20/20 unprepared letters" and move the letter individually to the "prepared" column using the gray right-facing arrow button next to the voter's name.