All commercial business mail must be brought into the business mail entry unit (BMEU[1]). This includes all First-Class Mail, Standard Mail, Package Services, and any mail paid with permit imprint. YOU CANNOT GIVE BUSINESS MAIL OR PERMIT IMPRINT MAIL TO A LETTER CARRIER OR DEPOSIT IT IN A COLLECTION BOX!

You must take your mailing to the Post Office where you hold your mailing permit[2]. For most mailers, this will be your local business mail entry unit, but if you’re in a small town you may have to take your mail directly to the retail window. If you are taking advantage of destination entry discounts[3], first you must go to the office where you hold your mailing permit. That office will verify and accept your mailing, and then you can take your destination entry mail to the correct postal facility.

TIPS
--Call first! Find out exactly where you need to go[4] and the best hours to bring your mail. Many local Post Offices and smaller business mail entry units have restricted hours, so an advance call to coordinate the best time to bring your mail there will work best. Most business mail entry units are open during business hours and even into the evening. Also ask about parking, especially if you’re mailing in the evening. Many letter shops and commercial mailers mail between 4 p.m. and 8 p.m. and the BMEU gets really busy.
--In some large metropolitan areas, business mail entry units have separate entrances or counters for commercial mailers and small mailers. Look for the signs.

Find Your Business Mail Entry Unit[5]

What to take with you[6]

What happens when you get there[7]

Checklist for mailers[8]