The client field can be added by following these steps:

1. Access the TMM Store (tap here to learn how)
   
2. Scroll down to the "Single Items" section and tap on the "Add Client Field" row but if you want to see any discounted bundles that include this add-on then:
   
   
   1. Tap the button in the upper right corner to open the store assistant
      
   2. Then scroll down to and tap the Client Field row
      
   3. Next tap the button to return to the filtered store listing
      
   4. Finally tap the add-on you are interested in from the bundles or single items section
      
3. The details page will open where you can read more about add-on and view screenshots. When you are ready to make the purchase then tap the button in the upper right corner and follow any prompts provided by Apple to complete the purchase.
   

Buying this add-on allows you to generate reports with total mileage and total reimbursement for each client.