On computer-delivered Writing you delete with backspace and you can rewrite a sentence in place. On paper you cross out and write above the line; a messy rewrite costs time and the last paragraph often dies. Practise the mode you booked: a full typed Task 2 in 40 minutes, or a handwritten one with crossing-out you can still read. On computer-delivered Reading, highlight is usually one colour. Use it on the deciding sentence, not a whole paragraph, and not five colours you then have to decode. The paper, the timings, and the 250-word Task 2 minimum do not change. Practice IELTS is a computer Writing and Reading tool. It is not the official familiarisation test, not a booking page, and not Listening or Speaking.
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.