Reflexive pronouns are words like myself, yourself, himself, herself, itself, oneself, ourselves, themselves, yourselves etc.

Use

A common use of reflexive pronouns is to talk about actions where the subject and the object are the same person.

The old woman killed herself. (Here the subject and the object refer to the same person.)
I went to the shop to buy myself some clothes.

Emphatic use

A reflexive pronoun can be used as subject or object emphasiser.

The Minister himself said this.
I myself did the work.
I will see the President himself if I have to.

By oneself, by himself etc

The expressions by oneself, by himself etc can mean either ‘alone’ or ‘without company’.

I would like to spend a quiet evening by myself.
He said that he could do it by himself.

My own, your own etc

There are no possessive reflexives. Instead, we use my own, your own etc.

He always cooks his own food.

Reflexives not used

Certain verbs cannot be used with reflexive pronouns in English. Examples are: open, sell, concentrate, feel etc.

Your book is selling well. (NOT Your book is selling itself well.)
I feel strange. (NOT I feel myself strange.)

Themselves/ourselves and each other/one another

There is a difference between themselves/ourselves and each other/one another.

They spent hours talking to themselves. (Each of them talked to himself/herself.)
They spent hours talking to each other. (Each of them talked to the other.)