The World Wrestling Federation had been known as such since 1979 when it was simplified as a company name from the World Wide Wrestling Federation (WWWF). However, in doing so, the company would put themselves in line for a future legal battle with the World Wildlife Fund, who were also trademarked with the acronym, WWF.
In 1994, the World Wildlife Fund insisted that the World Wrestling Federation sign a legal agreement ensuring the Federation limit their use of the WWF acronym outside of North America. In return, the World Wildlife Fund agreed not to pursue further litigation against the future-WWE and permitted them to continue to utilize the WWF name and logo in the company's homeland and in certain other circumstances.
The Federation, already struggling financially in the mid-nineties, had no wish to enter into further litigation. Therefore in McMahon's view, his company were forced to sign this agreement under duress. An agreement which would damage his company's profitability.
What this amounted to was the WWF ignoring the agreement they had signed with the World Wildlife Fund. The WWF logo and name was all over events and merchandise worldwide.
When the WWF became a hot commodity again in the wrestling boom period of 1998-2001, they drew attention to themselves from the World Wildlife Fund and found themselves in court once more.
The charity were successful in obtaining an injunction to remove McMahon's company's rights to the 'WWF' initials. Several months later, the London Court Appeal denied WWE the right to challenge the injunction to give the company rights to the initials inside North America.
With no way to market themselves, the WWF had no choice. They had to immediately change their name. So, the World Wrestling Federation became World Wrestling Entertainment.
McMahon, who has always wanted to be seen as a multi-faceted entrepreneur and not only a wrestling promoter, decided to embrace the change and use it as an opportunity to amplify the "entertainment" aspect of his business.
The now-WWE launched a huge marketing campaign, selling t-shirts and other merchandise bearing the slogan "get the F out", to highlight the new name.
Although they had changed their name, WWE faced further issues with the marketing of archival products bearing the WWF initials. In particular, the use of the WWF "scratch" logo, in use between 1998-2002, became prohibited on all WWE properties.
This meant archival WWE footage, bearing the "scratch" logo had to be blurred out which ruined the enjoyment for the viewer, due to the sheer volume of t-shirts and signs bearing the logo during the 1998-2002 period.
WWE secured a victory, earlier this decade, when the court of appeal, permitted the use of the WWF name and "scratch" logo in archived footage.
Like it or not, WWE seem themselves as an entertainment brand in 2018 and it is entirely possible that a re-brand would have occurred in the 2000's even without the World Wildlife Fund's intervention.
The WWE brand is more financially successful than the WWF one ever was. In the latest financial quarter in 2018, WWE recorded record revenue of $281.6 million. For that reason alone, the WWE name is here to stay.