Short answers, pulled from the story.
DC Comics released World of Krypton on the 1st of January 1979. This four-issue story marked a quiet revolution in the American comic book industry by promising a beginning, middle, and end before a single page was printed.
DC Comics coined the term maxiseries to describe longer formats like the twelve-issue epic Camelot 3000 published on the 1st of January 1982. This format distinguished itself from shorter miniseries by allowing for greater depth of storytelling that was impossible in standard six-issue runs.
Watchmen and The Dark Knight Returns were released on the 1st of January 1986. Alan Moore and Dave Gibbons delivered the twelve-issue masterpiece Watchmen while Frank Miller presented the four-issue prestige format series The Dark Knight Returns.
The writer typically remains constant throughout the run while the artist may change. This dynamic allows for a consistent narrative voice even when the visual style shifts, ensuring that the story remains coherent despite changes in artistic direction.
A few limited series have been done in an anthology format though these remain rare exceptions. These anthology limited series challenge the traditional structure by presenting multiple stories within a single run often exploring different characters or themes within the same universe.