webkit in CSS3 and what is the exact reason to use it.

webkit is vendorbased prefixed of google crome like other also for mozila and opera are

respectively -moz- and -o-

There are some stylings that vendors start implementing before it actually starts getting implemented. And these stylings are recognised by browser only with the vendor prefix, -webkit- being the one used for Chrome. This prefix will basically be used when the style is local to chrome browser, and you want to implement that.

For example you can use it for transctions .Follow the link

https://www.w3schools.com/css/css3_transitions.asp