You can just request the copy of your past invoice from your app.

It will automatically be sent instantly on your registered mobile address.

APP -> My Rides -> Past Trip -> Select Trip -> On top Right you will see an option to re-send invoice.

Alternatively, you can raise a support ticket here.  It will take 1 working day to process it. 

If you request via app, it will delivered instantly on your registered email

Tip :

In case you would like to change / update your Email ID, you can update the same from My Profile Section. Then request invoice again. Invoice will be sent on new email address.