Alice looked at herself in the mirror.
They enjoyed themselves at the beach.
We use reflexive pronouns when the person who does something, and the person who has something done, are the same. Note the difference between:
They looked at each other.
They looked at themselves.
In the first example, each person looked at the other people; in the second example the each person looked only at himself or herself.
These are some examples of the reflexive use:
I hope you enjoy yourself on holiday.
Can I have a biscuit, please? – Go on, help yourself.
I’m going out now, children, so behave yourselves.
We use reflexive pronouns to give emphasis to the subject, to stress that the subject worked alone.
I did all this work myself.
She designed all the decorations herself.