Where they provide exams that can be included, they have certain partnerships with exam centres. Details of this will always be provided on the course page, so make sure you are able to travel to the exam centre before you include this in your cost.
If you have a course with exams included or you have added these on, when you are ready to take your exams, contact them and they will book them for you.
On some courses where external exams aren’t available, it means they don’t have partnerships with exam boards. You will need to get in touch with the exam centres yourself, as you will sit the exam as a ‘private candidate’.