Hello, fellas. In English, necessity can be expressed using must, have to, and have got to. For the use of must and have to has ever been discussed, this session is going to focus on that of have got to.
(More on the use of must and have to: https://englishtips4u.com/2014/06/09/grammartrivia-the-use-of-must-and-have-to/)
Even though have got to also carries the meaning of necessity, it is more typical to use have got to in spoken and informal English.
1) I have got to take the IELTS test.
2) She has got to study hard.
In speech, have got to is usually pronounced gotta and have is omitted.
We gotta go to the bank.
Betty Schrampfer Azar, Understanding and Using English Grammar: Third Edition
Betty Schrampfer Azar, Fundamentals of English Grammar: Third Edition