A tract in FARMapper is a named group of shapes on the map. Basically, it is the bucket that holds the individual polygon shapes. You can use it in any way you like. For example, you can separate owned ground, leased ground, pivot ground, dry ground etc. into different tracts. You can also have multiple farms in your project with a separate tract for each of them.
Tracts are minimal units used in KML or CropScape integrations, which means that you can select any tracts for these functions, but not individual shapes.
In order to use full Tracts editing functionality you will need to log into the system using a Google, Facebook or Twitter account. This will also allow saving of the project so that you can work in stages.