Plans are not hard to create.
Check what they want and look at drawings normally supplied.
You normally dont need the full detail presented by some draughtsmen.
Plan, elevations, dimensions, window sizes, sanitation details, footing details and materials being used.
Sometimes drainage needs to be indicated.
Check if they understand cob, if they dont give them references.
I find if you work with them they will be helpful.
How to create permit drawings
Pretty good, real info starts at about 4.29 mins.