Many Jeeps from the ’80s and newer have hydraulically operated clutch linkage. If this system has a leak or even trapped air it can fail, leaving you clutchless. First, check the fluid in the clutch master cylinder reservoir. If it’s low or empty, you’ve found your problem. Check for a leak, and if you find one, use something to plug it or at least slow the flow. Now you have to add fluid and bleed the system to get all the trapped air out.