In OpenCV, the cv2.line() function is used to draw a line on an image. The function takes five required parameters:

• the image to be modified;
• the starting point of the line (specified as a tuple of x and y coordinates);
• the ending point of the line (specified as a tuple of x and y coordinates);
• the color of the line (specified as a tuple of Red, Green, Blue values);
• the thickness of the line.