It means front-end interface design. The first thing that users who enter your site will see will be the design of your site, it is the name given to the visible faces of the website created through programming languages such as CSS, HTML5. In general, it is created by means of programs that manipulate photographs and provide drawing, or with the privilege of special programs developed for front-end design.
The generally visible face of the site is called the front-end. Turkish words such as web design, interface design or frontend design can be used as equivalent to this word. There are many advantages to having your site designed by front-end developers. You get the look you want and you don't have to deal with constant revisions, saving time and money.