Monologues can be either long or short, and can be delivered at any point in a play. They are often used in Shakespearean plays, where they are often used to soliloquize or to express the character's inner thoughts and feelings.
Monologues can also be used in more modern plays, where they can be used to create a sense of intimacy between the character and the audience. They can also be used to provide exposition or background information, or to build suspense.
Here is an example of a monologue from Shakespeare's Hamlet:
"To be, or not to be, that is the question:
Whether 'tis nobler in the mind to suffer
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles,
And by opposing end them. To die, to sleep—
No more—and by a sleep to say we end
The heartache and the thousand natural shocks
That flesh is heir to, 'tis a consummation
Devoutly to be wished. To die, to sleep—
To sleep, perchance to dream—ay, there's the rub,
For in that sleep of death what dreams may come
When we have shuffled off this mortal coil,
Must give us pause."—Hamlet, Act 3, Scene 1
This monologue is a perfect example of a character expressing their inner thoughts and feelings. In this case, Hamlet is contemplating whether or not to take his own life. He weighs the pros and cons of both sides of the argument, and ultimately decides that life is worth living, even with all of its troubles.