Whether you take the IELTS academic or general test, in both task 1 and task 2 of the writing exam, 25% of your score will come from something called coherence and cohesion.
If you look at IELTS websites and YouTube videos, you might learn that cohesive devices are very important and that you should use as many of them as possible.
Some people had posted their IELTS essays for others to give feedback, and one of them included a screenshot from a bad website that gives you an estimated band score for your IELTS writing.