1

When we report what someone else said without using their exact quotes, we use Reported (or Indirect) Speech. Because the original words were spoken in the past, we usually shift the tense 'one step back' into the past.

2

Present Simple becomes Past Simple. 'I like tea' becomes 'He said that he liked tea.' Present Continuous becomes Past Continuous. 'I am working' becomes 'She said she was working.'

3

Past Simple and Present Perfect both shift back to the Past Perfect. 'I went to the store' becomes 'He said he had gone to the store.' Pronouns and time words also change (e.g., 'tomorrow' becomes 'the next day').