Converting Figma or PSD designs to HTML, CSS, and Bootstrap involves translating visual layouts into functional web pages. This process typically starts by slicing and exporting assets from the design file. HTML provides the structure and content, CSS styles the elements, and Bootstrap, a CSS framework, offers pre-built components and responsive grid systems to accelerate development and ensure cross-browser compatibility. Careful attention is paid to replicating the design's pixel-perfect details while ensuring clean, maintainable, and semantically correct code.