Reported Speech also called Indirect Speech or indirect discourse , is a means of expressing the content of statements, questions or other utterances, without quoting them explicitly as is done in direct speech.It is used to communicate what someone else said,think or believe but without using the exact words. A few changes are necessary; often a pronoun has to be changed and the verb is usually moved back a tense, where possible.

For example, He said "I'm coming" is direct speech, whereas He said he was coming is indirect speech.

Reported speech is usually used to talk about the past, so we normally change the tense of the words spoken. We use reporting verbs like “say,tell“, “ask“, and we may use the word “that” to introduce the reported words. Reported speech doesn’t use quotation marks to enclose what the person said.
For example:

When reporting questions, it is especially important to pay attention to sentence order. When reporting yes/ no questions connect the reported question using “if”. When reporting questions using question words (why, where, when, etc.) use the question word.