As Mumbai is quite far from Agra where the Taj Mahal is located, it is not possible to do an overnight trip to the Taj Mahal from Mumbai. The quickest way to get to Agra from Mumbai is to take a flight to Delhi and then take a train or drive to Agra. Here's a sample itinerary for a 2-day Taj Mahal trip from Mumbai.

Day 1: Mumbai to Delhi

Take a morning flight from Mumbai to Delhi.
Upon arrival in Delhi, you will be picked up by a private car and driver .
Spend the rest of the half day exploring Delhi , ( India gate , kutub minar , Lotus Temple , Parliament House, President House ) help of a local guide. After sight seen Drive to Agra
Overnight stay in Agra.

Note : Tajmahal closed on friday . if next day is friday then drive directly in Agra , sight seen in dehli next day

Day 2: Agra and Taj Mahal- Delhi airport

early morning visit sunrise vi Taj Mahal, one of the Seven Wonders of the World, later comeback Hotel for breakfast , fresh up then again continue to sight seen Agra Fort.
In the evening, drive back to Delhi and drop off at the airport for your return flight to Mumbai.
Note: It's important to check the opening hours of the Taj Mahal before planning your trip, as it is closed on Fridays. Also, the travel times mentioned above may vary depending on your mode of transportation and traffic conditions.