How to delete a world on Minecraft.
Open your Minecraft game through the shortcut or launcher. On the main menu, click on the Play or Singleplayer button.
Select the Worlds tab and search for the world that you want to delete. Click on the Edit button with a pencil icon for that specific world.
Now scroll down the world settings to the bottom. Click on the Delete World button.
After that, click on the Delete button for the confirmation dialog.
Your world will be permanently deleted from Minecraft.