An owner's draw is money taken out of the business by an owner for personal use.
What separates it from a wage
A wage is a cost of running the business and reduces profit. A draw does not. It is a reduction of the owner's stake, taken from money the business has already earned.
This is why a business can be profitable and still have very little in the bank: the profit was real, and then it was drawn out. See profit and cash.
Why it must be recorded as a draw
A draw miscategorised as a business expense understates profit, which understates tax owed and overstates how much the business can afford to spend. It is one of the most common bookkeeping errors in an owner-operated business.
Marking such a transaction correctly is covered in marking a transaction personal.
Which businesses use draws
Draws are how sole proprietorships and most partnerships pay their owners. Corporations generally pay owners through wages and distributions instead, and there the split is constrained by reasonable compensation.