A manager can motivate an employee by using both intrinsic and extrinsic motivation, depending on the type of employment. Finding ways for the employees to actually enjoy their job is probably the best way to motivate. Typically, if an employee enjoys their job, they are more likely to perform their job more efficiently. If it's a job that is hard to find ways to make more enjoyable, using extrinsic motivation such as a higher pay or rewards upon performance is an excellent motivator. Also, in some cases, it is possible to use negative consequences as a way to motivate employees. It could lower their morale, but using such tactics as threatening to cut hours can increase the employee's performance.
From what I have seen, most places of employment use extrinsic motivators for their employees. Generally, the motivators they will use are rewards or increases in pay during reviews for the employee's performance. Intrinsic motivators such as finding ways to make the job easier or more controlled are commonly used as well, but generally extrinsic motivators would lead to a higher performance in this day and age. If an employee believes that they could get a higher wage for better performance, they are more likely to improve their performance accordingly.
The use of intrinsic and extrinsic motivations are very important for any place of employment. Being able to motivate your employees to perform at a higher level is key to any type of company. The higher performance level, the better the company. Because of this, if management can find things such as ways to make the employee's job easier, ways to make the employee's job more enjoyable, benefits or rewards that can be given to the employee for better performance, or wage increases for a better performance, it'll not only motivate the current employee, but could motivate future employees through knowing that the company is willing to help with motivation for the job.