Modal verbs are auxiliary verbs used to express necessity, possibility, permission, ability, and other related ideas. Some common modal verbs in English include:

Can: Can I go to the party?

Could: Could you pass me the salt?

May: May I come in?

Might: It might rain later.

Must: You must finish your homework before watching TV.

Should: You should eat more vegetables.

Would: Would you like some coffee?

Will: I will help you with your project.

Shall: Shall we go for a walk?

Ought to: You ought to apologize for what you said.

These verbs add nuances to the meaning of the main verb in a sentence.