How to in korean?

All of the following words mean 'I am sorry' :

죄송합니다

죄송해요

미안합니다

미안하다

미안해

미안

The between 죄송합니다 and 미안합니다 is formality. The 죄송 ones are more formal than compared to 미안 ones.

The above list can be considered as the formality level decreasing with 죄송합니다 being the most formal and 미안 as the most informal.

: If you listen natives speaking, you can often misunderstand their pronunciation. They seem like pronouncing ㅂ as ㅁ and ㅁ as ㅂ because the sound differences are so tiny that it often gets mixed.