Clear aligners are an alternative to braces for straightening teeth. In children, teeth move more easily than in adults, so any type of appliance can be used successfully. One of the recent innovations of the Invisalign aligner system is early treatment with aligners in the mixed dentition, while the child still has some baby teeth. The aim of this treatment is to correct the shape of the dental arch, which is often part of the bite problem at this age, and to make room for and align the permanent teeth that have already come through. The results are excellent, and children prefer aligners to traditional removable appliances – they're comfortable and invisible.
This answer is for general information. Your own case needs an examination by an orthodontist.