While it's certainly possible to create music on a laptop using a mouse and a QWERTY keyboard, this isn't exactly ideal. Clicking in notes manually or attempting to play them on computer keys may just about work for a rough demo, but for anything else, a MIDI controller is essential.
Using a MIDI controller like a keyboard or a drum pad is not only a lot more tactile, but features like faders for expression and velocity sensitivity and built-in high-quality piano sounds, synth sounds, orchestral sounds and more simply make the music production process a million times better.
