Fantasy Football with my kids?

So my 3 kids (ages 8 to 13) would like to play fantasy football this year. I’d love to get them involved and do a small family league, but I’m not interested in giving them all separate login’s and separate e-mails, etc. just to play FF. So I’m hoping that somewhere there’s a site that allows a commissioner to set up a league where the individual players don’t need separate login, etc. Does anyone know of such a website? Thanks in advance and apologies if someone has already asked this before.