Filing Date

This is the date a filer submits a financial disclosure report to the supervisor or senior legal counsel for review, usually the date the filer eSigns the report in FDM.

the date of receipt in the Office of an application which includes (1) a specification containing a description and, if the application is a nonprovisional application, at least one claim, and (2) any required drawings

-- see MPEP 506 for more

The date when a sufficiently-complete patent application reaches a patent office. MPEP 506.