Do your research to find out who you should send it to. For example, if you are sending in a resume, look around online to figure out the appropriate person. If you can’t find a person, it’s acceptable to call the company and ask who the letter should be addressed to.
You may also need to at a suite number, such as STE 118.
USPS recommends at least an 8-point, legible font. [8] X Research source
However, you can use hyphens if the street number calls for it. [10] X Research source You can also use a hyphen between the 5-digit zip code and the 4-digit extension.
Your word processing software should have templates for printing on both labels and envelopes. Pick the template that matches the labels you bought, then type out the address for both the sending address and return address. Alternatively, pick the template that matches your envelope, then type in the addresses and print it.
Keeping it uncreased also allows the employer to make copies more easily.