When you sell a screenplay, it means that you have entered into an agreement with a production company or a studio to produce your script as a film or television show. The specifics of the agreement, including the terms of payment and the rights granted to the production company, will be outlined in a contract.
Once the screenplay is sold, the production company will begin the process of turning the script into a finished film or TV show. This can involve hiring actors, directors, and crew, scouting locations, and completing all of the other tasks necessary to bring the script to life on screen.
If the film or TV show is produced and released, you will receive payment according to the terms of your contract. This may include an upfront payment as well as additional payments based on the performance of the film or TV show.
If the screenplay is not produced, you will not receive any further payment, but you will retain the rights to the script and can try to sell it to another production company.