The most well-known dummy text is the 'Lorem Ipsum', which is said to have originated in the 16th century.
Due to its widespread use as filler text for layouts, non-readability is of great importance: human perception is tuned to recognize certain patterns and repetitions in texts.
If the distribution of letters and 'words' is random, the reader will not be distracted from making a neutral judgement on the visual impact and readability of the typefaces (typography), or the distribution of text on the page (layout or type area). For this reason, dummy text usually consists of a more or less random series of words or syllables.
Obviously I'M Web Designer. Experienced with all stages of the development cycle for dynamic web projects.