When you create a project in Datamaker, you have the option to change the default date format for the project. However, you are not able to change the date format once the project is created.
When you create the project, you will need to click on the blue right arrows, below "Project Description", to extend the create project window.
Once you have expanded the screen, you will see an entry for Date Format. You will then be able to change the format to YMD or YDM, or any variation of YMD. Once you click on the save icon, the date format will be set to the new format you changed it to, for the life of the project.