I saw this post on how to create a dodecahedron, although I cannot replicate this process in Blender 3.0
The Tool Shelf menu does not have an option to set the Object
Source, Here is the menu:
How created the object:
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this is how you do it:
after you added regular solid, in the left bottom corner you can open that window, here you can see the "source":
The manual calls the window the "Adjust Last Operation Panel" although people often call it the "Redo" panel. You can use it to adjust any operator, but only until you do something else.