Speaking from our own experience, you can’t be a passive McDonald’s franchisee. Every McDonald’s potential franchisee will need to complete at least thousands of hours of training before he/she would be approved to acquire a franchise and only if he/she has the financial resources to acquire a franchise. It could take years before one would get a single store franchise. Until the franchisee eventually has acquired multiple stores and established his/her own management team, the franchisee would have to put his/her nose to the grindstone and work his/her ass off every day. I won’t call it a passive investment by any stretch of imagination.
If you have specialized knowledge in a certain topic, you can put together an online course to teach others. For example, if you have experience in real estate investing, you can create an online course “Real Estate Investing 101”. The benefit of an online course is that once you create the course material, you can sell it to as many people as you want.