Noises are impossible to advise about online. You have to hear the noise to know what direction to go into.
Seek the help of a technician at a shop near you for further guidance.
You could have an internal engine rattle, a heat shield rattle and so forth.
RepairPal Certified shops can diagnose and repair your 2013 Ford Explorer. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.