The working part
What a web developer does
A developer turns the agreed design into working code. For a simple site, that means pages that load quickly, adapt to different screens, use a clear structure and send forms to the right destination. The code also needs sensible security and accessibility, because a page is not finished if customers cannot use it reliably.
The role becomes more visible when the website has logic. An ordering system must handle collection, delivery and chosen times. A booking or quote form must collect the right details. Payments need a checkout and a route to the owner's account. Logins need to recognise users, while an admin screen has to let the business change information without exposing private controls.
This is why development is not simply “putting the design online”. It covers what happens after the tap: how information is checked, where it goes, what is stored and what the business can do with it.