Products can be added to the list of service tasks either from the desk interface or with the app. It is recommend to do it through the app as it makes it easy for the technician to add the items used on the task while they are performing the work.
App (iOS)
From a task, tap Producst > Add > Toggle performed > Select the product and provide any additional details/notes if required > Save
App (Android)
From a task, tap Repairs > Tap the menu in the upper-right corner > Add product > Select the product and provide any additional details/notes if required > Toggle performed > Save
Desk
When viewing the task go to Work > Edit service tasks > Add service task.
Double click on the product field and select the applicable product and perform it.