You can configure vCenter Server from the vSphere Client and from the vSphere Web Client.

What you can do depends on your deployment.
On-premises vCenter Server
You can change many of the vCenter Server settings, including licensing, statistics collection, logging, and more.
vCenter Server in VMware Cloud on AWS
VMware preconfigures vCenter Server instances when you create an SDDC. You can view configuration settings and advanced settings, and you can set a Message of the Day.