You can ask for a default money judgment as soon as the tenant's time to file an Answer runs out. Your tenant has 5 days from when they were handed the Summons and Complaint (not including Saturdays, Sundays, or court holidays) to file an Answer. If they don't, on the 6th day you can ask for a default judgment.
You need the money judgment to try to collect the past due rent from your tenant's paycheck, bank account, or in other places they have money.