I wants to know about web filter which help us from the point view of internet safety, which block adults sites automatically.
You need to look up the configuration of your browser and/or firewall. Most, if not all, browsers allow you to set up security options either entering forbidden urls or using words to block content.
Your firewall should have a similar functionality
When I used Windows, my Internet Security/Antivirus had a parental control feature. It usually worked pretty well, although at one stage it blocked me from my own innocent and frankly boring site. Still, if you’re trying to protect children, it’s definitely best to err on the side of caution.
You can buy any external firewall, it is best.
I tried it a few years ago and found it very restrictive; my daughter was trying to do her homework and about every site she tried to visit was blocked. We removed the software; why not install some and test it?
Buy an external firewall as suggested. Ensure that you have a good antivirus running too as kids tend to download a lot of stuff. You can try kaspersky or quick heal or any other antivirus you prefer. And make sure you run malwarebytes occasionally too.