The main features of this custom app include the implementation of basic working agreements such as user registration, work with contracts and user administration, as well as the ability to accounts top up, payslips calculations, systematized work with documents, and the billing area of the admin, which allow you to track all payment transactions and accounting settlements in the system. Later we also integrated more payment functions such as Twint, Cash, and Bank Transfer with billing, which makes this project a convenient way to conduct financial operations.