So how do I know what universities want? Start by reading about the university, the course you want to study and the "entry profiles" as these will give you information about the type of student the university is looking for. Universities also want the truth so do not lie about your abilities and they want your writing so do not ask someone to write the personal statement for you. Some areas to cover include why you want to study this subject, what your future career plans are, what you do in your free time, what skills you have (academic and non_academic), what's interesting and/ or different about you.
A PS is one of the most important components of your application because this document, when written correctly, will offer your readers, namely the admissions committee members, a quick glance into your life story so far and which direction you plan to take. You are inviting the reader to share your experiences as you disclose who you are as an applicant. Through your PS, you are providing them a general picture of your background and qualifications, knowledge of which will allow them to evaluate your suitability for admission to their school accurately.