Under the rule of golf 24-2b, a golfer is entitled to free relief from a cart path if the ball comes to rest upon the path or the golfer's swing or stance is inhibited by the path. A golfer's stance is deemed to be inhibited if any part of his foot comes in contact with the path.
After deciding that relief from the cart path is desired or necessary, the golfer must find the nearest point of relief that moves the ball no closer to the hole and mark that point with a tee.
The golfer is entitled to one club length of relief from that spot, which is usually marked with another tee. The golfer must drop the ball from shoulder height at any point in between those two tees as long as the ball is not being dropped in a hazard or onto the green.
A golfer may take this relief with no penalty.
A golfer does not have to take a free drop when the ball comes to rest on the cart path, although it would be a good idea to avoid injury and damage to the club.
If a golfer decides the nearest point of relief would put him in a bad spot to play his next shot, he can play the ball from the cart path. Playing from the cart path is usually done only at tournaments when money or other such prizes are on the line. In casual play, it is a good idea to just take a free drop. Your clubs will thank you.