To create a business requirement for your website, you must define what your eCommerce needs at this moment. If you require a structural improvement, you should focus on creating a new high-level requirement. It could be, for example, to start optimizing the website loading to get better positioning and improve your search engine marketing. On the contrary, if you only need to improve a specific aspect within an area, you should create a new low-level requirement, analyzing the options that can give you the result you want. Following the previous example, once you focus on improving the website's loading, you can focus on how to lighten the weight of the images.