You need to create your Statement of Purpose as per the SoP rules or SoP Guidelines. There are many universities in the UK, USA, Canada, New Zealand, Australia and other countries that want you to write the statement as per the given instructions. You need to follow those instructions and if you do not your statement will be rejected.
Generally speaking, SoP guidelines are meant to make the statement more target-oriented. You are expected to include only relevant details. You will have to be very careful in creating it (For the best SoP Writing Services, rely on SoP Writers).