If tax agent clients' employers report through Single Touch Payroll (STP) and the clients are linked to ATO online services through myGov, the ATO will send them a myGov Inbox message to let them know:
  • their end of year payment summary (income statement) has been marked by their employer as "Tax ready" and can be used in their tax return; 
  • if they have more than one job, their other employers may still need to provide them with a payment summary; 
  • they need to include all income in their tax return; 
  • they can access their income statement in ATO online services through myGov, or the tax agent can give them the information; 
  • they do not need to give the tax agent their personal myGov login details to access their information.

If tax agent clients do not already have myGov accounts, the ATO says agents should let them know they do not need one for the agent to lodge their tax return. Tax agents can access their employment data and lodge for them once their information is "Tax ready".

Source: https://www.ato.gov.au/Tax-professionals/Newsroom/Your-practice/Informing-your-clients-their-information-is--Tax-ready-/