I would use a duster or wet vacuum cleaner to mop up excess water asap
Then work out if you park with the car facing the other way around if it cures the water leak. And so try and work out if the leak is by the bulkhead or windscreen and runs back into the the rear footwell.
If you look with a torch at the dash and below the steering wheel towards the door you may see the trail.
Some favourites are - top of windscreen, the rubber bung if you go to under the windscreen from under the bonnet, and the big rectangular seal for te intake for the blower - as found under the bonnet and centre bottom of windscreen.