The Add Menu or the Shift-a Menu Is Stuck at Meshes I'm new to blender so this question may have an easy answer but, when I press Shift+A on my keyboard, instead of showing all the menus, it only shows the mesh menu
or the add menu where all of the primitive objects are stored.
I use the latest version of blender and I am hoping to get help from you guys.
You are in Edit Mode. In this mode you are modifying the underlying geometry of your object. You can only add or remove geometry, other object types are unsupported. Change to Object Mode with TAB  or in the drop down menu there :