Navigation: ADMIN > SETTINGS > Client Portal Settings from the sub menu
The ability for clients to view and amend their contact and pet details is by default "allowed" in your client portal settings.
If for some reason this option has been unchecked, you will need to re-check it.
Look at the option to "Show client data" in the "Client Portal Settings"
If this box is UNchecked, check it again.
When you now go into the client portal, the "Your Data" tab will now be showing.