Mk:16:15:
"And he said unto them, Go ye into all the world, and preach the gospel to every creature." (KJV)
Mk:3:14:
"And he ordained twelve, that they should be with him, and that he might send them forth to preach." (KJV)
Lk:9:2:
"And he sent them to preach the kingdom of God, and to heal the sick". (KJV)
Where did He command to write anything? The only record of Him writing is when He wrote on the ground and the content of which is unknown to us:
Jn:8:8:
"And again he stooped down, and wrote on the ground". (KJV)
How many people could read back then or even now for that matter?
They were Jewish, the most literate people on earth, so literate that even the son of a poor carpenter could and did read scripture at the temple.