When memory
Erasure shows up in the Potter films, the spell you almost always hear is 'Obliviate'. In the most obvious on-screen example,
gilderoy lockhart tries to erase Harry and Ron's memories in '
Harry Potter and the Chamber of Secrets' — he says the word, the wand backfires, and the result is comic but also clearly a memory charm gone wrong that ends up taking chunks of his own mind. The filmmakers make the mechanics obvious: the incantation, a visible spell effect, and the immediate behavioral change.
Another clear instance is in 'Harry Potter and the Deathly Hallows – Part 1' where Hermione alters her parents' memories so they don't remember her and she can leave them safely. It's quieter and more intimate than Lockhart's pratfall, but the same core idea is on display: a deliberate memory change through magic. The movie shortens and simplifies the process from the book, but you can still see the emotional weight of a memory charm at work.
Beyond those two, the films refer to memory charms and the Ministry's Obliviators more broadly, and often imply off-screen obliviation after incidents. In practice, if someone on screen visibly forgets something right after a spell is cast, it's intended to be 'Obliviate' or another unnamed Memory Charm; the visual language the directors use — a dulling of expression, a pause in action, rapid cutaway — signals that a memory wipe has occurred. I love how those scenes range from slapstick to heartbreaking, and they always leave me thinking about the ethics of erasing a life’s memories.