IELTS Writing is marked on four equally weighted criteria. Task Response (Task 2) or Task Achievement (Task 1) asks whether you answered the task and developed the ideas. Coherence and Cohesion asks whether each paragraph has one job and whether ideas connect without a stack of "firstly" and "on the one hand." Lexical Resource is range and precision of vocabulary, not a memorised "band 9" list. Grammatical Range and Accuracy is a mix of sentence types with few slips. A single overall practice number is less useful than four separate marks. Use the four marks to choose tomorrow's drill. Practice IELTS shows those four on a scored Writing test. The marks are practice estimates, not official bands.
Take 1 free scored test (Writing or Reading) at https://practice-ielts.com. Then $14.99 for 3 months of Writing + Reading. Not official IELTS.