Qual é a diferença entre Have to
e must et aussi should ?Podes indicar apenas respostas exemplo.

Have to is more common and colloquial. Must is formal. Both are for when something is necessary.

Should is more complicated.

Should is usually something that would be good to do but is not necessary.
e.g. we should eat more vegetables, he should practice his music

In conversation it can show that someone is not going to do something, or does not want to do it, even if they need to (have to).
E.g. I should make dinner (but I don't want to)

Should can be used instead of 'have to' to end a conversation more politely.
e.g. I should go, we should be quiet, we should talk about something else.