So I'm writing a screenplay and I'm not sure if I can hide my character's name. Do I have to say it in the screenplay but just mention that we don't get their name until later. I've heard I should just use a nickname, but when their "name" is revealed it already comes as a nickname.
A screenplay is written primarily for the production crew, not for the audience. So you don't have to be afraid of spoiling any plot points by using the real name of the character even though the audience isn't supposed to know it yet.
Switching the name of a character mid-script would be confusing for the production crew. It would just lead to misconceptions about how many actors need to be cast, who needs to learn which lines and who needs to be present for which scene.
You have several options at your disposal:
You could use a descriptive name: main character, maid, angry customer. Not all characters need names. While it's a bit unusual to refer that way to long-lived characters (often they do have a name), if you are using this approach with other characters, that could go unnoticed.
You could use the initials to refer to the character.
If this screenplay is already assigned to some actors, you could use the names of the people who will be playing them.
A solution I've seen is as follows: When the character's first introduced they use the alias.
Bob enters the library. Standing at a bookshelf is a LIBRARIAN, filing some books. BOB Do you have any books? LIBRARIAN Shh.
then, later, they're re-introduced with both names:
Bob enters the library, followed by the two thugs, each armed with a heavy cudgel. The Librarian is at the central desk, and Bob walks swiftly to it and joins her. BOB You need to get out of here. Those two are dangerous. LIBRARIAN I'll be better able to help you if you just come behind the desk. He moves behind the desk, to see the Librarian is holding a Detonics ScoreMaster in her lap. BOB What? Who the hell are you? LIBRARIAN Susie. BOB Can you use that thing? SUSIE (formerly LIBRARIAN) Sure. Susie stands up and shoots the two thugs in one swift and easy move.
And from then on you use the second name.
I think this depends on the exact scenario.
Is this like Clint Eastwood's character in Sergio Leone's "Dollars Trilogy", where we just never learn his name, even though he's got friends that seem to know it? If so, you would coin a reference to this character for use in the screenplay and credits. "The Doctor" would be in this mode.
Is it that one of the named characters has speaking parts while masked, or hidden? Your cast will need to know which actor plays this part, so you'll need to tell them up-front who this is, even if you label their lines as "masked woman" or "man's voice from the darkness". But you could probably label their lines differently while they're speaking anonymously, to keep the secret from people who are privy to only part of the script.
Is it that the character is completely unknown until some big reveal, like Deep Throat or QAnon, and they have no un-masked role until that point? You could perhaps use their code name prior to the reveal, and then a combination after:
QAnon (from darkness): It is time you learn who I am!
Reporter: Reveal yourself!
QAnon/Noam Chomsky (steps into light): It is I!
All: (Gasp) Shouldn't it be It is me?
QAnon/Noam Chomsky: Trust me on that.
But again your upfront cast list will need to make it clear that one actor is to play both parts.
It's not out of the question to hide identity in the screenplay. In the script for Pygmalion all the principal characters are preset, but referred to by generic names: GENTLEMAN, NOTE-TAKER, FLOWER GIRL, MOTHER, DAUGHTER, and the script only refers to them by their names in scene 2 - Colonel Pickering, Henry Higgins, Eliza Doolittle, Mrs Eynsford Hill, Clara Eynsford Hill.
Yes of course you can, there are multiple ways to do it. My favourite example is in one of the most famous movies of Max Ophuls: "Madame De..."
Even in the title of the movie, the character name of the leading actress is incomplete. It's hidden throughout the whole movie.
Every time a character is about to pronounce her name, something happens (horse-drawn carriage passing nearby, a train about to leave...) Every time her name could be read somewhere, the remaining part is incomplete due to a series of coincidences.
This element contributes a lot to the storyline of this particular movie which is in my opinion the best example and I'd recommend you to watch it.
In this case, in the screenplay, you could just say Madame De... Or use whatever name you want, but keep it constant, because the screenplay is for the production crew not for the audience. So if you want to hide the name to the audience you can do it by changing what's written in the actual script. The naming of the character is only relevant for production.