When using a word processor, text is entered and the software immediately displays what the document looks like. Some core packages are like the corner restaurant that's always been there, and you can't imagine the building without it, but others are more recent and may come and go over time, but LaTeX itself is always there to provide a solid highly expandable framework for them to enable almost any document requirement you may have.
There are numerous packages to create virtually any document element and packages are written and updated frequently. The interior is adaptable and ever-changing because LaTeX makes use of a package system to extend its functionality and features. This may make LaTeX seem antiquated, but you can think of it as the classic brick foundation to a modernized building. The current version of LaTeX is 2e which was first released in 1994. This makes LaTeX a more user-friendly experience than TeX while maintaining the typographic power of the TeX backend. LaTeX was then developed in the early 1980's by Leslie Lamport as a higher level language that utilizes TeX, but makes it easier to use through introducing predefined document styles, sectioning, indexing, automatic cross references, automatic numbering and a variety of other useful features. It was designed after Knuth observed that the digital typesetting software at the time was not up to the typographical standard of previous typesetting techniques and set out to design such a system. TeX was created in the late 1970's by Donald Knuth as a typesetting program for text and mathematical formulae. LaTeX lends itself well to the creation of templates that do not require advanced knowledge of LaTeX to use and manipulate, allowing a novice LaTeX user to create beautiful documents and learn LaTeX as they go. The numerous customization options in LaTeX allow for the creation of a diversity of document types with precise control over layout and formatting. This results in professional-looking documents that are of a different class to the output from a word processor.
Unlike a typical "what you see is what you get" word processor such a Microsoft Word, LaTeX uses a plain text markup language (akin to HTML and CSS) which is compiled into a PDF document using optimal typographical rules. It is commonly used by scientists, engineers, software developers, mathematicians and other professionals to produce lengthy and technical documents, but its utility is not restricted to that space. LaTeX, pronounced lay-tech, is a system for creating high quality documents.