Regimental staff officers were expected to be able to read, write and do basic arithmetic (add and subtract). Checking the census, we find that nearly all Confederate staff officers had been merchants, attorneys and clerks in civilian life. Much the same is true for field and company officers, as well as orderly sergeants.
Since staff duties were not primarily clerical, these officers should not have required any assistance to prepare a document. These men possessed extensive clerical experience, and could complete a requisition in a matter of moments.
The same sitaution should have been true at brigade HQ and even division HQ.