To request Manufacturing outhorization letter

I am Birhanu Assaye am from Ethiopia and working on Desktop, laptop, printer and server Retails and Distribute in Ethiopia.  Currently the Federal and regional Government office  and Universities request Manufacturing Authorization letter for Huge BID participation. For the last 3 years we are simply imported from Dubai and retail and sell to the government offices. Know a days every higher bids request the MAF letter. Please help me how to get the letter.