It depends on a number of factors:
Are you already pre approved by a lender?
Do you have all your paperwork in order if your lender asks for it?
Do you have cash for the down payment + cash to pay closing costs?
Is your credit score above 620?
Have you been at your job for at least 2 years?
Is your debt to income ratio 40% or less?
All of the above questions will make it easier for your lender to complete the loan process and get it to underwriting quickly. If any of the answers to the above questions is No, then you need to fix it so it becomes a Yes. The shortest time frame to complete a loan application averages 30 days. If any of the answers to the above questions is No, then expect a time frame of 3 months or longer.