How to convert the cube (or any object) into a static mesh asset

• Summon a cube
• Select the cube you have summoned in the game world.
• In the Details panel, go to the "Mesh" section and click on the arrow next to the mesh asset name.
• Select "Create Static Mesh" from the dropdown menu. This will create a new static mesh asset that represents your cube.
  
• u can now use this to create special objects