Select your client  via "Dropdown Arrow" from the left side OR via "Clients" from the right side.

Client's "Setting" is located below client's name

General Contact Details. In this case we are filling the details for a company and so the signatory must be noted.

"Settings > Contact Details" for Individual entity -

"Settings > Contact Details" for Company, Partnership, SMSF, Trust, and Partnership.

Note that Primary Contact/Signatory is the person who receives, signs the tax return, SPFRs and used as a contact in tax payer's declaration on tax form.

User (tax agent) need to "Untick" the box if he wants the tax form to be sent to himself as agent of the client.

For FOREIGN addresses State and Postcode are not required on tax forms (also not required to fill under Settings>Contact details). ATO requirement is that postcode is  maximum 4 characters long. Workaround for this kind of issue is to left empty the said fields (State and Postcode) and add this either Line 1 or 2.

Related article:

Define Client Relationship

Adding clients Archiving Clients / Delete Client