If you wish to apply for a scholarship for your Master's or MBA studies you should first carefully select the business school and make sure that it offers scholarships for which you qualify. However, this should be just one of your selection criteria along with many others see: How to Select Schools
Before you start your application to the business school you should clarify what the application process is for scholarships. Most often there are two types - either no additional application for scholarships is required, meaning that all applicants are automatically considered for the available scholarships, or there are separate requirements and steps you have to take in order to be considered for a scholarship. Usually the scholarship applications are reviewed after the admission decisions have been taken.
In most cases the additional requirements for a scholarship application are an essay, and a presentation or project you have to submit. Sometimes a separate application form (or a section in the admission application package) must be submitted. Check whether you can apply for more than one scholarship and whether you can combine scholarships if you are eligible for more than one type.
Bear in mind that there may be an earlier application deadline for scholarship applicants as well as higher requirements for test scores (especially for merit-based scholarships). You might also have a different contact person for all scholarship questions, but you can always initially ask the Admissions Office for the details and the right contact.
See also: How to Finance Your Studies