If you’re referring to Accessibility in terms of users with differing abilities - such as Hard of Hearing, or Colorblindness - and you’d like to provide suggestions/feedback on those topics specifically then check out this article:
To be clear, everyone is already expected to follow the In-game Code of Conduct in Blizzard games. The Social Contract you’re referring to is simply an in-game presentation and a reminder of the existing rules and recommnedations for player behavior.
NEW SOCIAL CONTRACT
When players first log in to World of Warcraft after the 9.2.5 content update goes live, they will be greeted by the new Social Contract. This contract will need to be read and accepted before a player can continue into the world of Azeroth. The contract outlines behavior that will help make your experiences more positive and provides an outline of behaviors that are not acceptable within the game. While you should only need to accept it once, there may be a future point where you’ll need to reaccept the contract to continue playing.
If you encounter players who are being inappropriate or harassing you right now, then please do report them using the in-game tools provided.
There are improvements coming in 9.2.5, but that doesn’t mean you can’t report harassment right now. Thanks for helping keep the game a friendly place to explore and play.