https://help.gosimpletax.com/hc/en-gb/articles/360000571120-Submitting-Tax-Returns-as-an-Agent

https://help.gosimpletax.com/hc/en-gb/articles/360000571120-Submitting-Tax-Returns-as-an-Agent

Click on SETTINGS Indicate that your filing Tax Returns on behalf your clients     Enter your Practice Name, Agent ID, HMRC User name and SAVE      Click on EDIT to go back to the main screen    Click on VALIDATE MY TAX RETURN  Click YES to proceed    Enter your HMRC Password    Click on FINAL STEP: CLIENT APPROVAL