If the background of a text in OneNote is highlighted in green, OneLatex interprets the content of this text as settings. For this to work, the format of the text must be in JSON and the property names must match those used by OneLatex.

If you copy the settings and paste them into OneNote, it will look like this:

See Creating your first document with OneLatex for a step by step instruction how to copy and paste all settins.

See Settings in OneLatex to understand the concept of how settings are applied in OneLatex and what the different settings mean.