Unless a university has "rolling admissions," applications are filed, reviewed (yes, often by a Work-Study Student or clerical worker) for completion. Then completed applications (all additional documentation such as test scores & letters of recommendation received) are reviewed to ensure ALL prerequisites & admission requirements are met.
Only completed, qualified applications are reviewed by committee after the submission deadline. The obviously best candidates typically are accepted & notified first, then remaining candidates evaluated to the limits of their intake (plus margin for those who do not confirm acceptance). Last come waiting list candidates who may be accepted if they have vacancies or additional non-confirmations.
Schools with rolling admissions policies usually have similar procedures, but the committee meets more often, reviewing smaller batches of completed & screened applications at a time.