Eldritch Cannon Question

Once you place the cannon, can the player switch between the different types of cannons every turn? No where in the description does it say they cannot choose to change the type on there turn. Is this a DM decsion?

It depends on which version of the class you're using.

In the 5e version from Tasha's Cauldron of Everything, you choose which type of cannon it is when you create it. The feature does not describe any means of switching between them, so that's not a thing you can do. If you want a different kind, you need to create a new one (which destroys the old one, up until level 15 when you're allowed to have two at a time).

In the 5.5e version from Eberron: Forge of the Artificer, the cannon doesn't have a set "type", so there's nothing to "switch". Every cannon you create is capable of using all three abilities, and you choose which one to activate when you use a bonus action to activate it.