There different openings in different films however there all fit different categorize of opening structure.
A narrative opening- Which is used commonly known is when a film goes straight to the film no black backgroundit goes straight into thefirst scene. It would start to get to know the location of where the film sets and the characters that are included in the film and the setting.
A discrete title sequence- is when the opening has nothing to do with the narrative the plot but its in the same theme of the film. They are mostly full of edits throughout the sequence.
CREDITS OVER BLANK SCREEN- This is more basic to do as it all it is a blank screen that start with title rolling its often has a soundtrack or sound effects.
STYLISED EDITING- These are not easy to do as they take a lot of time to make in post production. They are heavily edited and amazing to see.