Documents and format for ead formal letter

[amankof]

i’m on F1 and currently married to a US citizen and she’s pregnant for me. Considering her state she’s likely to give birth soon. Bills are piling up and projections into the future clearly indicate the likelihood of my family facing severe hardship.
We attempted to expedite the ead process but USCIS got to us via email stating that we supply enough evidence.

please I need help with,
1. Format of cover letter
2. evidences to submit