Often used for sensitive financial and legal documents, Certified Mail with Return Receipt is a trackable, secure mailing option that requires proof that someone has physically received and signed for the letter or package.

When you use this service for your small business mail, there are restrictions on the types of mail services and add-ons you can use as well as how you can ship the package. The USPS also has rules and laws on forms the post office must fill out, how delivery attempts occur, how long the post office retains the mail and how the signature is logged.

Basic Certified Mail Rules

The USPS places some basic rules and restrictions on Certified Mail. First, you'll only be able to use domestic First Class or Priority Mail; regular postage stamps are an acceptable option. You do not have the ability to get insurance for Certified Mail, so this service isn't made for securely mailing expensive items like Registered Mail is. However, you do get the ability to track your mail online or via phone to have some peace of mind during the mail's journey, and you'll be able to verify each delivery attempt, successful or not.

You can combine Certified Mail with the Return Receipt and Restricted Delivery services. The Return Receipt requires the signature of whoever accepts the package and costs $2.80 for you to receive a physical copy or $1.60 to get an email receipt. Restricted Delivery, which costs $8.80, lets you state a specific person – like the named recipient or an authorized representative – who must sign for your Certified Mail letter or parcel. If you do not restrict delivery, anybody at the address can legally sign for the Certified Mail.

Rules for the Shipping Process

Unless you use an online shipping service like Stamps.com that offers special mailing labels and forms, you'll need to take your letter or package to a local post office and purchase Certified Mail with Return Receipt in person.

At that time, the post office worker will fill out a Certified Mail receipt called USPS Form 3800. This form contains basic information about your shipment including the recipient's address, postage fees, add-on services and a postmark as well as a tracking number you can use online. The barcoded label from this form will go on your letter or package.

The post office worker must also fill out USPS Form 3811, which is the Return Receipt. It includes the recipient's address, details about mail services and a delivery section. The latter is where the recipient will sign and where the courier will log other details about the delivery attempt. This form will be attached to your package for mailing, and depending on whether you opted to receive electronic or hard copy proof of delivery, you'll get an email or postcard from the USPS upon delivery.

Rules and Laws for Delivery

Due to signature requirements and the possibility of multiple delivery attempts, it usually takes anywhere from three to 10 days for a Certified Mail parcel to arrive. There are generally two delivery attempts before a final notice to pick up the mail, and the USPS will hold the mail for a total of 15 days. As soon as the recipient signs for the item, you'll get your Return Receipt emailed or mailed to you, and you can also always track the mail's status – including delivery attempts – through the USPS website.

The postal carrier will make the first attempt and request a physical signature from the recipient or authorized individual. If no authorized person is available to accept the mail, the USPS will leave a reminder in the recipient's mailbox. The recipient can either visit the post office to get the mail or follow the directions on the notice to request another delivery attempt. If neither occurs within five days, the USPS tries to deliver a second time.

If the recipient is unavailable the second time, then she will receive a final notice and will either have to pick up the item in person or request a final redelivery attempt. Once 15 days have passed without a successful delivery, the USPS will mark the Certified Mail as undeliverable and return it to the sender.