I’m from Iraq I want to visit Macau do I need a visa or I can got in arrive ?

You can get a visa on arrival with proof of HK$/MOP 5,000 in cash, hotel reservations for the whole duration of stay and a ticket leaving Macau. The visa fee is HK$/MOP 100 for individuals payable in cash.

But according to Hong Kong rules:

c) where the application is for a transit visa/permit, he/she holds an onward ticket to the place of his/her destination unless the destination is the Mainland of China (the Mainland) or the Macao Special Administrative Region (SAR).

Can I visit Macau by ship for few days with Hong Kong visa-free policy but returned back to Hong Kong in few days and air out to other country?

In that case immigration will generally accept a ticket leaving HK.