Yep. Basically, when you delete a file, it removes the connection or link to it in its system. But the file doesn’t really disappear until the computer happens to use that space to write something new.
An analogy might be… It removes your address from the phonebook, so no one can find you. But it only bulldozes the home incidentally when it builds a new home.
(In reality, it’s slightly more difficult, because technically a file isn’t a single home, but closer to a bunch of homes spread out across a state. So, if it’s spread out enough, it can be difficult to retrieve it after it’s lost. This is why “defragging” was popular in the past with HDDs – it would help pull all the homes together into one neighbourhood. Anyway, because of being all over the place, you can imagine that maybe 2 of the 100 homes get rebuilt at a time as you keep using the space as normal, making the file harder and harder to retrieve over time until it’s simply impossible.)
The way secure deletion programs work is by not just deleting the file but using the space straight afterwards, too. To follow the analogy, they are doing the demolishing then building random nonsense over the spot a few times, so your actual house is like 20 buildings worth ago. And then when it finally deletes the last nonsense house, the history of your building is lost to time.