“For such an iconic thing that strikes both fear and wonder in American culture, how can no one know where it came from?” [Source]
Helen Peters was the sister-in-law of Elijah Bond, who held the patent for the Ouija board, and who was a business partner of Charles Kennard, who claimed to have invented it. 
Peters was present and played a pivotal role on two different occasions crucial to the birth of the Ouija board. The first was when the board was given the name “Ouija” — by her, in consultation with the board, at a meeting of potential investors. The other was in applying for a patent for the Ouija board, when she demonstrated the operation of the board at the patent office, in order to prove that the board worked. 
Peters has been described as an affluent woman from a “society background” who, along with her brother-in-law, was an investor in Kennard’s fledgling Ouija board company.
According to Kennard, the board got its name when he, Helen Peters, and Elijah Bond were hanging out at a boarding house. They needed a name for the board and decided to ask the board what it wanted to be named. Peters was described as a strong medium, and the answer she got from the board was “Ouija”. They then asked the board the meaning of the word and the board answered “good luck”. Later, Peters pulled out a locket she was wearing with an image of a woman and the word ouija below it, which has been traced to the signature for “Ouida“, a pen name for Maria Louise Ramé, a British author who was known for her salons and her flamboyant lifestyle. 
In the second instance of rescuing the Ouija board for Posterity, Peters traveled to Washington DC patent office with Bond, since the patent office had responded that “action on the merits is suspended until proven by a working model to be operative”. Peters was able to demonstrate the board actually did work by spelling out the name of the chief patent officer, which was supposedly unknown to them. 
In 1891 she married Ernest Nosworthy. She moved to Denver in 1896 and lived there until her death in 1940. She is buried at Denver’s Fairmount Cemetery. 
Ramée was a British-born writer who penned dozens of overheated romance and adventure novels set in exotic locales, plus critical essays, animal stories, and books for children. Her books were best-sellers on both sides of the Atlantic; even Queen Victoria was a fan. According to The Bloomsbury Dictionary of English Literature, in her later life she lived mostly in Italy, indulging in “an expensive and affected life with dogs and frequent hopeless infatuations.”
Eccentric and ostentatious (she loved purple writing paper and Lord Byron), scorned by many male writers, but beloved by female readers, Ramée and her signature apparently became something of a talisman for forward-thinking women like Peters. 
Hmm, “overheated romance and adventure novels set in exotic locales”?
Where are these Ouida novels?
Here are two of them, and the LOC link has a few more:
- Santa Barbara [and other stories] by Ouida https://www.loc.gov/item/06033312/
- https://en.wikipedia.org/wiki/Under_Two_Flags_(novel) (This was her most famous.)