The Independence Visitor Center is the first destination I recommend to friends and family visiting Philadelphia. The Center is free and open daily. It’s close 
not only to the Liberty Bell but also to many important historical and cultural Philly sites. Since the Center is located on Independence Mall, you can enjoy free panaromic views of Independence Hall and the Philly skyline from their terrace balcony.
I recommend watching their short video about Independence Hall’s history before doing the National Park Service tour. You can make reservations at the Visitor Center for the NPS tour if you didn’t register in advance.
Next to the movie theater is a quirky interactive exhibit for all ages that celebrates famous early Philadelphians. The Info Desk staff are multilingual experts at recommending Philly attractions based on your interests. I had lived in Philly for several years before discovering that you can get discounted tickets to a hundred attractions by buying tickets at the Info Desk.
The Center gift shop is one of the best spots for classic Philly tee shirts and souvenirs. Look for a Rocky statue by the shop entrance and take a selfie if you can’t make the hike up to see the Rocky original by the Art Museum steps.
Another Philly icon, the Phillies Phanatic, is a featured sculpture by the snack/food concession in the back. If you are driving here, the indoor Independence Mall Autopark parking garage is a great, reasonably priced option.
It’s also worth a stop to see the 2 Philly history murals by Mural Arts near the parking lot entrance.