Hi Kamlesh. I'm Greg, an installation specialist, 9 year Windows MVP and Independent Advisor, here to help you.
You'd need to make sure the children have a Standard Account:
https://www.windowscentral.com/how-change-user-...
There are some options here further down the page for WIndows 10:
https://www.raymond.cc/blog/disable-f8-key-to-b...
There is also this older registry edit that you could try. I would set a System restore point first so you have an easy way to go back in addition to reversing the change in the registry:
http://thetechnologygeek.org/disable-windows-sa...
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.
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