How can I show the color in the solid view mode?
Color means? are you asking about the texture of an object?
Select object > Apply a texture > Go to Display in solid mode panel in viewport top > Choose texture
If you want solid color then
Select object > Object properties > Viewport display > Change color > Go to Display in solid mode panel in viewport top > Choose object
If you choose random, Random color will be shown for all objects in the view port
thank you very much!