What are indicias and how do they work?

An Indicia or Mailing Permit Imprint is a convenient way to pay for postage when you send bulk mail. This means you don’t have to run the mail through a meter, or buy stamps and affix them to the mail pieces. Just about anyone can apply for a permit. The USPS has an application online you can download to apply. There is an annual fee you must pay to use the indicia.
The post office has specific rules for the types of mail it can be used on, what an indicia says, and where it is placed on the mail piece. We will look at these below.
In general Permit Imprint mailings must contain at least 200 pieces or 50 lbs. 
The required minimum per mailing is:
200 pieces (or 50 lbs) for First Class, Standard & Non-Profit Mail

500 pieces for Presorted First-Class
Permit imprint indicia must read in the same direction as the delivery address on the mailpiece. The indicia must not encroach on reserved space (e.g., ACS participant code, delivery point barcode) if such a standard applies and can be placed in one of these positions:
a. Upper right corner of the mailpiece.
b. Upper right corner of the address area.
c. To the right of the address on an address label.
Permit Imprints can be downloaded from here: