Tradify requires an internet connection to send and retrieve data between mobile devices and the Tradify servers. Typically you will find your mobile device using WiFi where it can before using cellular data connectivity over your mobile providers network.
Even when used all day Tradify itself generally only transmits relatively small packets of text information when you are viewing, managing and saving jobs. However if you are saving large files, high quality photos and even videos from your mobile device to Tradify, or viewing job files on your mobile, these transfers can use a much larger amount of data. Furthermore, some detailed PDFs and videos that may have been transferred quickly via email on a desktop computer with fast internet connection might actually be very large when viewing on the job.
It is possible to see how much cellular data each app is using.
On Android simply go to Settings > Data Usage, and scroll down the screen to see a list your apps sorted by how much cellular data they have used recently.
On iOS simply go to Settings > Mobile, and scroll down the screen to see a list your apps sorted by how much cellular data they have used recently.