If you look for help writing SOPs for MBAs on the internet, you'll find hundreds of articles and blogs that claim to have the answers. Reading them will undoubtedly benefit you while also confusing you due to the abundance of advice. It will appear simpler and give you the confidence to write one on your own if you boil down the most fundamental two tips.
Start writing without any preconceived notions.
You've probably read a number of sample SOPs for MBA or other related courses you're applying to. If you start writing your admission while under the influence of those, you'll wind up with one that sounds identical. For an MBA, you'll need a statement of purpose that sounds distinct and genuine to you. So, free your head of any such influencing influences and give yourself some time to brainstorm.