At the base of every house there is the literal foundation of the home. The (most likely poured) concrete below the floor that has been, is currently, and will continue to hold your house steady and safe. Without a good foundation the rest of the house doesn’t even matter; it would simply be a pile of construction debris.
Assuming the foundation of your house was already good to begin with when you got your house, what can you do to maintain a good foundation?
The main goal when tending for your foundation is to ensure water does not get near enough to damage and weather it, as water is wont to do. Water can ruin your foundation by directly eroding the concrete, or indirectly by causing the soil beneath the foundation to swell or shrink causing unevenness in the foundation. Keep water out of your foundation’s area by ensuring that there aren’t any downwards slopes funneling water into the foundation. Use fill soil to terraform the area around your house so that the water trickles away from the foundation. Make sure you also avoid overwatering any grass or plants near the foundation of the house.