The safest way to get Hello Neighbor for free is through official sources:

Several reputable browser gaming platforms host free, playable versions of Hello Neighbor:

If you have Xbox Game Pass, PlayStation Plus, or Apple Arcade, Hello Neighbor is frequently included in these libraries. You can use a 14-day free trial of these services to play and beat the entire game for free.

The developers previously made early Alpha and Beta builds available for free download on their official website to test mechanics. What Does "Verified" Free Play Mean?