If you want to communicate with the job owner about a task you can easily do this by adding a note to the task.

When you add the note you can select to notify the job owner, this way all of the communication is tracked against the task.

Click here to view a step by step guide on Add a Note.

If you need to contact them urgently via phone you can obtain their phone number by clicking on the job supervisor's name which will direct you to a link with their details. 

NOTE: you may or may not have access to view their contact details depending on the job owners settings.