How are takeoff and stall different from each other?
On take-off the pitch is increased to increase lift, but only to a point well before stall occurs. An aircraft's minimum speed is defined by the maximum lift it can create before the flow over the wings stalls, and the high-pitch attitude is only attained when the aircraft flies faster than that. As soon as lift is sufficient for lift-off, further pitch increases are increasing the flight path angle. If the aircraft keeps accelerating during the initial climb, stalling is impossible.

Technically, both are very different. Their only commonality is that they involve high angles of attack.