So generally speaking, if you're a normal consumer user of tech, deleting a file just deletes a record on your hard drive that points to where the memory address that locates your data is. The data itself isn't actually deleted unless you do a memory wipe. It will eventually be overwritten, because any memory that isn't reserved by a set of records is considered "free" to the OS to overwrite, even if there was previous data there, but until that point that data still exists there.

You can truly delete a file by wiping the memory (usually done by taking the set of memory for the file and overwriting everything to some empty state). But the default that happens when you delete a file doesn't do this because it's computationally expensive to do this when there's no real reason to.

As a security tip, if you're ever trying to actually delete data from a computer in a way that ensures it's not accessible, you want to do a memory wipe and overwrite the entire drive to an empty state. Just "deleting" the files will actually leave all the data there and just delete the records that say where the data is. Anyone good with computers can recover all of that unwiped data despite there not being a stored record for it because the data is never overwritten. Always fully wipe your drives before transferring ownership of computers with sensitive info.