What's the best picture size setting to take pics of documents

that I will be uploading to send for legal documentation cause I'm needing to send a pic of hand written letter of verification to the health and human services department

12mp, it's the largest and will provide the most detail.

You may want to also look into an app called Cam Scanner.

https://play.google.com/store/apps/d...sig.camscanner

It's especially handy in cases where a regular photo doesn't show well, or if the ink is faded.