On most POS computers, Cortana is not required. Cortana is a virtual assistant created by Microsoft for Windows 10 Few use it, most in my experience that use a virtual assistant prefer Google assistant or Amazon Alex.
The big problem is that part of Cortana is SearchUI.exe. This piece of software will use a lot of your system resources and so can cause a significant speed loss on your computer. As such as a rule we turn it off but many other vendors leave it on.
If you do not use Microsoft Cortana search assistant, I would suggest that you try turning it off too. Instructions are here.