Can you still drive your car if the windshield has a crack in it? That all depends on the size, location and type of crack.
Large cracks that are in your view while driving need immediate attention. Same is true for cracks that threaten the structural integrity of the car. Windshields do help support the strength of the frame around the windshield.
When you have multiple cracks or cracks that spread to the edges of the windshield, contacting the professionals is needed.
For smaller cracks that do not spread, there are options for a possible fix rather than replacing. Check with the professionals for all your options.