There are many ways an opening would be shown in a film. One example of this is:
A narrative opening: An opening of a film with titles running through it. An example of a film which uses this: The Shining. The camera follows a car from a high angle and from it you can see massive mountains. During this the titles are running through it.
A discrete title sequence: A title sequence with the titles appearing in a different background, separate from the opening clips. Example of a film which uses Discrete title sequence: Se7en.
Titles over a blank screen: Titles running through a blank screen. An example of a film that uses this is Memento. After the blank screen, the blank screen disappears to the photograph and the title sequence still carries on.
Stylized Editing: When a film uses effects in an opening film. This is used to make the opening sequence look attractive to the audience. Example: Taking of Pelham 123.