A page builder is a visual, drag-and-drop tool built into a website platform that lets you lay out text, images, and blocks on a page by clicking and dragging, with no code. Popular ones include Elementor and Divi for WordPress, and the block editors inside most hosted platforms.
The appeal is real and worth saying plainly: a page builder puts layout in the hands of a non-technical owner, so you can change a headline, move a section, or add a testimonial yourself without hiring anyone. For many businesses that independence is exactly the point.
The tradeoff is weight. To stay flexible enough for anything, page builders tend to load a lot of extra code and styling on every page, whether a given page uses it or not, and that can slow a site down and drag on its Core Web Vitals. The convenience is genuine; the cost usually shows up in speed. A lighter website builder or a hand-built site trades some of that click-to-edit freedom for pages that load faster.
I build sites so the parts you will actually change stay editable, without loading a heavy builder on every page, because a page that is easy to edit still has to be fast for the visitor reading it. It is a balance, not a free lunch, and worth deciding on purpose.