Generally speaking, it is very simple to prove that children are studying in a kindergarten. The content of the certificate is generally that the child is studying in kindergarten. The content should say the child's birth date, study time, class, etc. Finally, stamp the official seal of the kindergarten.
In addition, it is not compulsory for children to go to kindergarten. Usually kindergartens accept children aged 3-6, which belongs to pre-school education and does not belong to the scope of compulsory education. However, many parents subconsciously think that it is natural for their children to go to kindergarten, and have never thought that their children will go to primary school directly without going to kindergarten. Moreover, the system in each place is different. In some places, children need to provide proof that they attend kindergarten when they go to primary school. It is necessary for parents to understand this.