The graphic computer interface that became common with Apple's Macintosh computer is sometimes known as WYSIWYG, where "WYSIWYG" = "what you see is what you get." The following chart shows an Ngram query on both "WYSIWYG" and "what you see is what" (Ngram won't handle phrases of more than five words).
You can see "WYSIWG" on the rise starting in the mid-1980s, which coincides with the MacIntosh, which was released in 1984. But "what you see is what you get" extends back into the 1970s.
What's going on?
In the fall of 1970 Flip Wilson debuted a comedy show on NBC. He was perhaps best known for playing a character named Geraldine, a sassy, brassy, black woman. Geraldine has a number of catch phrases, including "The devil made me do it" and "What you see is what you get." WYSIWIG!
Did the computer industry get the phrase from Flip Wilson, or was it independently invented? Inquiring minds want to know.