Yes, you can log into Minecraft using your username. When you create a new Minecraft account, you will be asked to choose a unique username, which will become your login name for the game. You can use this username to log in to Minecraft whenever you want to play the game, either on a single player world or on a multiplayer server. To log in to Minecraft, you will need to enter your username and password on the login screen. Once you have entered your login credentials and pressed the "Log In" button, you will be taken to the main menu of the game. From there, you can start a new game, join a multiplayer server, or load a saved game.