Sharepoint customization for Intranet

I need help to create an intranet to centralize enterprise document and project management and let employees stay tuned to the company's activities. I would like the homepage to be customized and modern look. The future portal was also to become a single access point to a variety of corporate systems that employees used daily. The customer wanted their intranet to be mobile-friendly in order to provide their remote employees with all necessary functionality regardless of the device they use.