What is Interoffice Mail (and How Do You Send It?)

Though the US Post Office usually runs like a well-oiled machine, it’s not the best mailing solution for mail sent within a company. Instead, when a company has many departments or more than one office, they rely on an interoffice mail system.


What is Interoffice Mail?

Interoffice mail, also known as interdepartmental mail, is mail  sent within an organization or company. It isn’t a part of the US Post office, so postage is not required. Interoffice mail is beneficial for large businesses or organizations since documents often need to be sent to different offices or departments. 

For instance, most universities use interoffice mail to mail things such as seminar flyers or billing notices to different departments. Large companies also use it to mail important documents or packages among their different offices.

The benefits of interoffice mail include speed and cost-effectivness. I It’s faster and cheaper than using the US Post Office or other national courier services. Instead of important mail being mixed with mail outside of the company, interoffice mail is a private mail system within large organizations. This makes mailing important documents more secure and streamlined, resulting in less mailed items getting lost or delayed.


interoffice envelopes


How to Send Interoffice Mail

Oftentimes, companies that use interoffice mail have a centralized mailroom where the mail is sorted and distributed. There’s a variety of ways to send interoffice mail, and the protocol varies between companies. 

A common way to send interoffice mail is to place the mail in a designated basket or tray on your desk where it will be picked up by the mail person. Also, many offices will have departmental pigeonholes marked for outgoing mail.  

There are steps you can take to make the process more streamlined. For example, have all your envelopes facing the same way and stacked neatly. This saves the mail person time sorting and organizing your mail, which will get it delivered sooner. Also, if you’re mailing several  similar items that are going to the same department, it may be a good idea to secure them together with a rubber band. If you’re mailing copies of something such as a flyer, place them all in the same envelope.

Always mail items as soon as possible so they arrive at their destination on time.

Things to Avoid

Policies vary per company, but there are some rules of thumb to ensure the interoffice mail system runs smoothly.

 Interoffice mail systems are strictly for business purposes, so never mail personal items. Also, many companies discourage mailing anything breakable or hazardous, unless of course, these kind of items are in your line of business. If that’s the case, make sure to always follow your company’s protocol carefully.

The Proper Etiquette and Protocol for Addressing Interoffice Mail

Typically, businesses provide their own interoffice mail envelopes to keep things consistent. To ensure your mail is sent to the correct department, follow these addressing guidelines.


Interoffice Delivery Tips


  • On the interoffice envelope, you will see the fields ‘date,’ ‘deliver to,’ ‘department,’ ‘sent by,’ and ‘building address.’ Always fill in all that information so the mail person knows when it was sent, who it is going to, and who it is from. By including the department name and building address, you can guarantee your mail will be delivered to the correct site.
  • If you’re mailing a package, still include all this information but put it where you normally would on any other package. The sender’s return information should go in the upper left corner and the receiver’s information should go in the center.
  • Never assume the mail person will understand any abbreviations, acronyms, or misspellings. Write out the full name and address of the department or building and the recipient.
  • Finally, always write in clear, neat handwriting to avoid any confusion.


Interoffice mail template

Click here to download our interoffice mail template!


Envelopes Designed for Interoffice Mail 

For many interoffice mail systems, you need to use specific interoffice mail envelopes rather than standard business ones.

Most businesses use a button and string fastener envelope, also known as a tie closure envelope, as interoffice envelopes. This kind of envelopeis best for internal mail since their seals are reusable and don’t require adhesive.


To Note

Since interoffice mail is delivered by hand and doesn’t go through the wear and tail of regular mail, tie closure envelopes work great. However, they aren’t a viable option if you’re mailing something through the postal service since they are more likely to fall apart.


When using button-and-string fastener envelopes, remember they can be reused. Use a label to cover up the existing information to save costs. Once the envelope has been used to its capacity, remove the string and recycle it.

If you’re looking for interoffice envelopes that have adhesive rather than a string tie, try resealable interoffice envelopes these . TheRedi-Tac™ closure works for multiple uses and keeps your contents secure.


interoffice envelopes


The Future of Interoffice Mail

Thanks to digital technologies such as email and professional messengers like Slack, interoffice mail is less prevalent today.For certain documents and items, physical mail can’t yet be replaced, but it can be improved.

One way companies are improving interoffice mail is by implementing mailroom management software. For instance, iOFFICE offers a program that makes it easy to track packages, check in packages, notify employees of the arrival of their package, and look at mailroom trends. They also offer intelligent lockers that require a code to open, ensuring everyones packages are kept secure. 

Barcode technology is also becoming more common. When you use iOFFICE’s mobile app, you can create a barcode for every package, making it easy to track. The app also lets the package receiver digitally sign for packages.




Interoffice Mail is Here to Stay

Interoffice mail isn’t going away anytime soon, especially for universities and other higher education organizations. By having a streamlined process that everyone understands, it will continue to be the best way large companies and organizations distribute internal mail. 


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Lexie is a content writer for Blue Summit Supplies. When she’s not typing away at her computer, you can find her listening to music while lounging in a hammock or wandering around with her DSLR camera. She lives with her fiancé and adorable dog, Beau, in their cozy, candle-filled apartment.

1 comment

Ayaz Nadeem

Great 👍

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