Advance Planning Document (APD) refers to an Initial advance automated data processing planning document or Initial APD, providing a recorded plan of action to request funding approval for a project which will require the use of ADP services or equipment, including the use of shared or purchased services in lieu of State acquired stand-alone resources.
Further reading –
https://www.acf.hhs.gov/sites/default/files/ocse/apd_guide_2.pdf