What type of stud is placed below a windowsill to support its weight?

The type of stud placed below a Windowsill to support its weight is called a "window sill support stud" or "window jack stud." These vertical studs are specifically positioned to provide additional support to the Windowsill and redistribute the load to the wall framing. They ensure the stability and proper alignment of the Windowsill, helping to prevent sagging or structural issues over time.