Seeking an app to track billable hours

Hello, could someone please recommend an accessible app for tracking billable hours? If I am not clear, I am referring to an app that lets me track how much time I spend with clients and how much they owe me. I am looking for some specific features as well, such as the ability to sort my entries by week or month. I also need to specify which week or month to be examined. If possible, the ability to export entries to iCloud Drive or Dropbox, or email, would be great. I don't mind paying a small fee for the app, once someone else is sure it has the features I am looking for. Thank you!

Forum: 

#1 Freshbooks

I use and generally love Freshbooks, which you can find on the App Store. It does time tracking, project management, and invoicing, among other things, and a single-user license isn't very expensive at all.