setc name-or-number 

Stands for set color. Sets the color of the turtle’s pen. If the turtle has its original shape, it will change color to show the pen color. The input can be the name of a color or a number. If the input is a name, a quotation mark must precede it. The original pen color is black, or color number 9. The input can be an integer or a one place decimal. Decimal numbers give exact colors when the project is in “thousands” color mode. See 256 Colors vs. Thousands of Colors  in Section 3 of the User's Guide, and color.

Examples: 

setc "red
setc 12