IELTS is one of the toughest English proficiency tests accepted by over 9,000 organisations worldwide, including schools, universities, employers, immigration authorities and professional bodies.

IELTS is basically of two types - Academic and General, IELTS academic is taken by students who want to apply to a university at the undergraduate or postgraduate level and IELTS General is taken by people who want to take up work related training in an English speaking country.

To check the preparation books & study material, You can go through with the given below link.

https://studyabroad.careers360.com/articles/ielts-preparation-books-and-study-materials

Good Luck!