To enter your mileage:

If you have a Business tab:

• Go to the Business tab
• Click Continue > I'll choose what I work on
• Click Start/Update next to Business Income and Expenses
• Click Edit next to your business name or enter your business information.
• Scroll down to the Business Expenses section and click Start next to Business Vehicle Expense.
• Proceed through the interview until you get to the Mileage Records for your vehicle screen.
• Select Yes to Did you keep track of your mileage when you used this vehicle for business?
• Select Yes to Did you document your business miles for this vehicle?
• On the next screen, you will either select that you want to enter the total miles or the beginning and ending odometer reading for 2016.

• Go to My Account > Tools > Topic Search
•  Type mileage deduction in the topic search and click Go. 
•  Click Edit next to your occupation or enter your business information.
  
•  Continue through the interview until you get to the Any Vehicle Expenses or Sales? page or Vehicle Summary page.
• Click Edit if you have already entered your vehicle.  Answer Yes if you have yet to enter our vehicle information.
• Proceed through the interview until you get to the Mileage Records for Your Vehicle page.
• Answer Yes that you kept track of your mileage and you documented it.
• The next page will ask how you want to enter your mileage.