William Thomas Riker of Star Trek: The Next Generation is the Enterprise's first officer and resident bearded heartthrob. Growing up in Alaska, he was quite the outdoorsman, but he chose to leave the majestic wilderness from his youth to "boldly go where no one has gone before." Riker was known as "Number One," informally with Picard. Depending when in the timeline or on which Federation starship he was aboard, he's sometimes just "Captain." To his friends, he goes by "Will," his preferred name, as stated in the Season 6 episode "Chain of Command, Part 1." However, Riker wasn't always called "Will" in the series. In fact, part of the original plan for the "most charming man in Starfleet" was to address him as "Bill."
Source：https://www.cbr.com/star-trek-tng-riker-will-bill/
