How can I let players create and move their own tokens in roll20?

When I run D&D online, I want to delegate players to have control of their tokens.

If one of my players tells me they cast flaming sphere, I want to be able to tell them to go find an image of a flaming sphere and put it on the map as a token.

If one of my players turns into a dire wolf, I want to be able to tell them to replace their token with a dire wolf token with the of their choice.

If one of my players uses summon nature’s ally and summons a bunch of critters, I want to be able to tell them to put the critters on the map.

I believe that using the roll20 console I could do this work for the players, but I want to spend my time doing other things, for example running the next player’s turn while this player generates a moonbeam token.

When I’ve tried to use roll20, I always had to create tokens for my players and then delegate them permission to use the tokens, and I frequently got it wrong and had to redo it.

Is there a way to configure roll20 to let my players create and manipulate tokens of their own?