If you'd like to preview the client portal for a specific contact to ensure your branding is up to date, or see the items assigned to them, you can do so from their contact profile in your address book.

You can click on a contact (from the job or anywhere else) and click preview in the Client Portal section here:

This will allow you to view the client portal for this contact in a preview mode, so you can see exactly what the client will see when they log in:

NOTE: You'll want to be sure you have this option checked in Settings › Branding to show their entire history with you, even after a contract or questionnaire is completed. This setting is per brand so be sure to enable it for each brand if you're using multiple brands.

Without this setting checked the client portal will only show open items and won't also show the History section.