It sort of depends on how I became a millionaire. IF I had to work for it, I'd be investing along the way. And then when I had the million I'd spend part of it on my children's educations. I feel bad for my daughter who can only take one class at a time right now. My son needs help with academic work but he's very smart and determined.
Once I had a single million dollars I'd invest it in "home grown" enterprises around the world. I can't find it today but there is an organization that helps people invest in "start up" enterprises around the world, making loans to private citizens whose businesses help small communities and the interest is low, unlike the big commercial banks. It is a way for individuals to bring prosperity to places that desperately need it.
Eventually I'd buy a modest house of my own and one for each of my children. I'd fix their cars like new or buy them new ones if they need it. I'd get myself a good vehicle, not necessarily a new one. And I get my books published. That is my "ideal" life is to get my books published.