A business website is mainly for public information, branding, service pages, portfolio, content, and inquiries. It helps potential customers learn about your company and contact you.
A web system is more functional. It usually includes login accounts, admin dashboards, databases, records, reports, workflows, approvals, and role-based access. Examples include POS systems, booking platforms, school portals, CRMs, and inventory systems.
Some businesses need only a website at the beginning. Others need a website plus a private admin system to manage daily work.