Be careful of memorised sentences.
There are some IELTS teachers out there who tell students to write an outline statement after the thesis statement. To be honest, this is not a good way to structure the introduction. Outline statements are only for true academic essays that are many pages long, like you would write at university (IELTS essays are short discursive essays)
Another reason why I advise not writing them is that they look like they have been memorised. The examiner is looking out for memorised statements and sentences. You could lose points on this in task response and lexical resource. To put it simply, you have to use your own words. The IELTS examiners are looking at how you can use language naturally and coherently.