some questions about reported speech
I have some questions about reported speech:

- If in direct speech, our reported speech is an emotional verbs like whispered, cry, laugh, and smile; how do we able to change that sentence to indirect speech.
For example:
" I am older than you," Sarah laughed.

- Do we have to change "tomorrow" to "following day" or it is a rule that everytime if we have this we should change it.

- what is the difference between "he said" or "he says"? When do use present simple or past simple of reported verbs.

Question

some questions about reported speech
I have some questions about reported speech:

- If in direct speech, our reported speech is an emotional verbs like whispered, cry, laugh, and smile; how do we able to change that sentence to indirect speech. 
For example:
" I am older than you," Sarah laughed.

- Do we have to change "tomorrow" to "following day" or it is a rule that everytime if we have this we should change it.

- what is the difference between "he said" or "he says"? When do use present simple or past simple of reported verbs.

Answer

To answer the first question only, you can use the simple past tense to report events in the past, with any appropriate verb, including the examples you gave, like whisper, sigh.

"Laughing" is a different activity to speaking whereas e.g. whispering, is a form of speaking.  So you could say  :

" I am older than you," Sarah joked.  or

" I am older than you," Sarah said, while laughing.

"joking" is a form of speaking.