Hi Karishma,
Thank you so much for visiting the Disney Parks Moms Panel with your question!
Downtown Disney is a vibrant dining, shopping, and entertainment area at Walt Disney World. There is no admission fee to visit Downtown Disney. There is a huge range of shopping options, from Disney stores such as the gigantic World of Disney and the hip Tren-D, to other fun stores such as LittleMissMatched and the LEGO Imagination Center. There is great dining at Downtown Disney - for a delicious sit-down meal, try Raglan Road which features Irish fare. If you are in a hurry, Earl of Sandwich is one of my favorite quick-service locations. Finally, there is fun entertainment at Downtown Disney. You might enjoy a round of bowling at Splitsville Luxury Lanes, or taking in the amazing show La Nouba by Cirque du Soleil. Please do note that both of these entertainment options do have an additional cost.
As to where to park, you should park at the place you intend to stay. If you are going to spend the day at Downtown Disney, by all means you should park there. If you are going to spend the day at a theme park, you should park at that theme park.
Have a wonderful time planning your vacation, Karishma! Please do not hesitate to ask if you have any further questions.