There are two parts in the IELTS academic writing exam: IELTS writing task 1 and IELTS writing task 2. Candidates are required to complete at least 150 words for Task 1 and 250 words for Task 2 to achieve a reasonable mark for any sorts of application.

You can find some links below that explain more about the structure, exam tips and things to avoid in the IELTS writing task 1. 

How to prepare for the IELTS Writing Task 1

IELTS Marking Criteria for Writing Task 1 

5 types of IELTS Writing Task 1 reports

IELTS Writing Task 1 tips

Paragraphing in IELTS Writing Task 1