~어/아야 되다 can be used to express should/must/have :

도와야 돼요 = I have to/should/must help

(verb is 돕다 = to help. This is a irregular ㅂ ending verb so it’ll change to 도와. 되다 will change to 돼요.)

You can also use ~어/아야 하다 to express should/must/have :

우리 서둘러야 해요 = We must/should/have to hurry

(우리 = we. 서두르다 = to hurry. 하다 will turn to 해요.)

The pattern 어/아야 지요 can also be used to express should/must/have :

문을 열어야 지요 = You should/have to/must open the door

(문 = door. 열다 = to open.)

In English, “should”, “have to”, “must” all have different degrees of meaning. In Korean, ~어/아야 되다 and ~어/아야 하다 and 어/아야 지요 can be used to mean, should/have to/or must. Therefore, when translating into English, whether to use “should”, “have to” or “must” can be determined by context.

As a sidenote, ~어/아야 되다 is more colloquial than ~어/아야 하다. Also, 어/아야 지요 has a meaning that is much softer than what the English word “should” or “must” or “have to” implies.

For example, the sentence, “방을 청소해야 지요” = You/I should/must/have to clean the room. (방 = room. 청소하다 = to clean.) However, the sentence has more of a meaning that is less forceful. It kind of means, “You know you have to clean” or “You know you should clean”. The 어/아야 지요 is sort of an indirect way of saying one should or must do something.