How long does it take underwriting to process or package a mortgage loan

Depends on the company and the complexity of the file. Some company's have a 24 hour turn around from time of submission to an UW decision some can be as long as 4 or 5 days.

Realistically with most lenders you should allow a minimum of 3-4 weeks from application to full loan approval and closing - part depends on how quickly you respond to requests for needed information and documentation.