Final answer:
Form 941 is timely filed if it is postmarked or delivered to an IRS-approved delivery service by the due date. It is not timely if delivered to an unapproved delivery service even by the due date, leading to potential penalties.
Step-by-step explanation:
Form 941, which is the Employer's Quarterly Federal Tax Return, is considered to be timely filed in several scenarios, such as when it is postmarked by the due date or delivered to an IRS approved private delivery service by the due date. However, it is not considered timely filed when it is delivered to an unapproved delivery service by the due date. This is because the IRS has specific requirements for approved delivery services, and using an unapproved service can lead to the form being considered late, which could in turn result in penalties for the employer.