I don’t like to write anything, so when I have to mail something, I want to print out the envelope. Unfortunately, Google Docs doesn’t have the venerable #10 envelope as a paper size. Never fear, the Envelopes add-on for Google Docs will save the day.
To get started, open up a new Google Docs document, and go to the Add-ons -> Get Add-ons menu.
Search for envelopes, and install the first choice. The company will be Synergy LLC.
Once installed, you can set up the current document as an envelope by going to the menu Add-ons -> Envelopes -> Select Size.
Normal sized envelopes in the US are #10. The add-on will resize the current document’s page size to match the envelope size. It will also set up the margins on the envelop correctly for the to address area and the from address area. Fill out the envelope, print, and you’re done!