Hi Beverly!
Thanks for your question and for visiting the Disney Parks Moms Panel!
There are a few options available to get to
Epcot from
Magic Kingdom. Your best bet is to hop the Disney monorail from Magic Kingdom to the Ticket & Transportation Center and then transfer to the Epcot monorail.
Or, you can take the Ferry across the Seven Seas Lagoon to the Ticket & Transportation Center and then board the Epcot monorail.
The monorail ride itself is only about 20-30 minutes but keep in mind the additional time for exiting the park, walking to the ferry or monorail, sail time or wait time, and gate security.
I would allow a good hour to an hour and a half to complete the entire process of exiting Magic Kingdom and entering Epcot. Please keep in mind that this is probably on the long end of my estimate and can be influenced by crowd levels and other factors.
I hope this helps and I wish you a Magical trip!!
Chris