Hasbro does not currently offer an official "My Monopoly" personalization service in the US. While Hasbro UK/Europe previously offered a "My Monopoly" service allowing custom property names and box art, this was discontinued globally around 2016-2017.
Creating a personalized game for personal use/gifting is generally tolerated. Selling custom Monopoly games infringes on Hasbro's trademarks (board layout, "Monopoly" name, Mr. Monopoly character, specific property names). Do not attempt to sell them.