The phrase "long form" refers to an extended or more detailed version of something. When describing a written piece, synonyms for "long form" may include "in-depth", "comprehensive" or "lengthy". These alternative expressions imply that the content delves deeply into a particular subject matter, covering it extensively and providing a thorough analysis. Furthermore, you could also use "extended", "detailed" or "prolonged" to convey the idea of a lengthier version with expanded information, offering a more comprehensive understanding. These synonyms enable writers and readers to explore topics in greater detail, fostering a deep appreciation for the subject at hand.