Canva.com has templates that you can use to make great certificates for your kid.

https://www.canva.com/design/DAC4NGp2lHI/vgKTSaDn-oguLbJsBAL04g/view?utm_content=DAC4NGp2lHI&utm_campaign=designshare&utm_medium=link&utm_source=sharebutton

Video showing how to edit the template