How can I avoid typing mistakes?
Obviously, if you're taking the computer-delivered IELTS exam, it's essential that your typing is accurate. If you find that you're making a lot of typing mistakes (known as 'typos') with basic words whose spelling you are very familiar with, then you know you have a typing problem, not a spelling problem. This can be a serious issue because it can sometimes be difficult to spot typos when you proofread. How to fix it?
1. Type more carefully. It's not actually necessary to type very fast to be able to write an IELTS Task 1 or 2 essay/letter in the time given. Slowing down a little will not only improve the accuracy of your typing but will probably help you to think more clearly too.
2. Teach yourself to spot these mistakes. This is a question of training yourself to look carefully at individual words when you're proofreading. You may need to slow down a bit during proofreading as well to begin with. Practice with old essays which contain mistakes without any spellcheck switched on on your device.
3. Improve your typing. There are plenty of resources (free and paid for) available online to help you train up your typing to a better level so that you improve accuracy. Check out this one, for example: https://www.typing.com/