Client and Task Management System

I'm looking to develop a clickup web-based organization system to help manage my small business more efficiently. I also need an iOS mobile application for on-the-go access. The system should have robust client management and task assignment and tracking capabilities... (Budget: $30 - $250 USD, Jobs: App Development, ClickUp, iOS Development, iPhone, Mobile App Development, Mobile Development, Objective C, PHP, Web Development)