Does Tencent Health System take effect immediately after it opens the minor mode?

Effective immediately.

Tencent Health System is the anti-addiction system, which aims to solve the current situation that minors are addicted to online games, so that minors can't rely on online for a long time to gain the growth of their personal ability in the game, improve the reward value, effectively control the online time of underage users, and change bad game habits that are not conducive to their physical and mental health.