In custom lists, you can create or upload special data for users to choose from as they complete forms. Depending on the structure of your form, a user can choose a single element of data that will automatically populate other form fields.
A custom list can be as simple as a list of appointment times, or as detailed as a worksheet-type listing of screw names, types and part numbers.
It is important to note that the mobile device must have a data connection, either via cellular or wifi, in order to use this feature.