Hi, 'to have someone do / doing something' is quite informal, but the difference is comparable to the difference between simple and continuous. - 'If you don't want to teach the children, just have them make a poster for an hour' (speaking generally, or a suggestion) - 'He doesn't want to teach the childen today, so he has them making posters' (right now) - 'When I went round, he had his kids working in the shop' (at the time that I was there). It's a very informal structure though and I wouldn't say it's so common. I hope that helps, I hope that helps.

The grammatical correct way of saying it is : Have someone do something.

The grammatical correct way of saying it is : Have someone do something