There are lots of different ways a player can develop foot dexterity and touch. Ball mastery, Cone work, Wall work are just a few.
One of the most important though (and easiest to do consistently) might be what we call Dad work [or mom work......lets call it 'parent' work].
This is just simply a 'parent' working with their child to establish some fundamental touches and footwork patterns, in a relatively controlled way and in a relatively small space.
There is one caveat; Your child must be ready for it, and be happy to do it. If you child finds it arduous, or it is done for more time than they can tolerate then the development from it may diminish. So manage it carefully.
Focus on different Inside of the foot touches