Can I apply for a patent for invention after applying for a utility model?

If you can't apply for an invention patent after your utility model patent is authorized, even if you do, it will be rejected. If you really want to apply for an invention patent, you can do it in the following two ways: 1, request.

Withdraw the application for a patent for utility model, and then immediately apply for an invention patent with the same content. Or 2, apply for a patent for invention, and claim the priority of the earlier applied patent for utility model, however, the conditions of this way

Yes; It must be within 12 months from the date of filing the previous utility model patent. Otherwise, this method will not work.