To manually Add Trip details, go to the Mileage tab from the bottom navigation menu.
From the MileageTracker™ screen, tap on the plus icon 
in the upper right corner of the screen, or tap on the New Trip from the hamburger menu.
On the New Trip screen, you will need to enter the starting location, then the destination.
If necessary, you can add additional destinations by tapping on the Add Destination icon
to track multiple locations mileage.
If you need to track the Mileage for a round trip, enable the Round Trip toggle 
As soon as you enter the addresses, the MileageTracker™ will automatically calculate the distance between the 2(or more) locations you have specified.
Once you are done entering trip details, tap on the Save icon in the upper right of the screen 
This will bring you to the New Expense screen, from where you can edit the Expense details relevant to this Mileage.
Once all the details for the mileage expense are entered, tap on the Save icon 
from the upper right side of the screen, or tap on Save option from the hamburger menu
If necessary, you can add a Comment to this Mileage Expense, by tapping on the Comment option from the hamburger menu.
Click here to learn more about adding comments to an expense.