How do I get a permit?

If you are going during the quota season (May 1 through November 1), you must apply online at recreation.gov between February 1 and March 15. The results will be emailed to you on March 23 and you have until April 30 to accept or decline the date(s) you got. Your credit card will not be charged until you accept the date(s). Note: you will also be emailed if you did not get a permit.

1. Create an account on recreation.gov
2. Log in and search for Mount Whitney
3. Select Permits and Wilderness
4. It will give you a choice of Day Use or overnight permits
5. Select the one you want
6. Enter the date or date range you want
7. Enter the group size (max size is 15)
8. You can enter your preferred date and 14 alternative dates
9. The permit costs $15/person. There is a non-refundable $6 application fee when you submit your application
10. Submit application and wait for results

Picking up the permit

Head to the Ranger Station that's just south of Lone Pine, CA.

In there you will pick up the permit. Have your permit number and ID ready. (They give you the permit number in the email) 

If you did not win the Lottery

The ranger station has unused permits available on a first come, first serve basis. IF ANY ARE AVAILABLE. You're best bet would be to call in advance and see what they are saying as far as availability goes. Here is their phone number: 760-876-6222
For example, if you want to start on a Friday, you're best bet would be to show up on Thursday and see if there are any unused permits available for Friday. It is possible to get one the day of but, it all depends on what's available.