@RussSharek some info on font licensing in the united states [this is not legal advice. just background info]

1. US copyright law holds that you cannot copyright the alphabet. It is not possible to copyright the shape of letterforms. For printed material or images, every font is unencumbered from the standpoint of the viewer, because the shapes of letters are always in the public domain.

2. What is copyrightable in the US is the PROGRAMS used to generate text (which is to say, the font files). Even though the design of the letterforms cannot be copyrighted, the font code that is used to generate those letterforms can. This means that embedding fonts, including in a PDF, has stricter copyright concerns than rendering them to a flat image or printing them.

3. Font programs are typically licensed, not sold. That means that you can only do things with them that their license allows. This allows fonts to be a little more restrictive in allowed uses because you can potentially violate the license even if you are not violating copyright by redistributing the font.

4. When it comes to “open” fonts, virtually all of them use the SIL Open Font License. This license allows you to use the font for whatever you want and redistribute it freely. It lets you make changes to the font, but may require you to change the name of the font when you do so (if the font author requested it).

Any font on Google Fonts uses the SIL OFL as do many others here and there on the internet. If you want a font that is truly fully unencumbered and public domain, the options are pretty slim.