Here's how to archive a client you no longer work with, and bring them back if they return.

Archive a client

To archive several at once, tap the select button at the top of Clients, choose Archive, and tick them.

What archiving does

Archiving tidies your Clients list. It doesn't hide or delete any of the client's records.

Hidden: the client is taken off your Clients list, and out of the list you pick a client from when you book an appointment or create an invoice.
Not hidden: their invoices stay in the Invoices tab, under Unpaid or Paid as usual, and can still be paid. Their appointments stay on your Appts calendar. Their walks and visits stay in your completed activities.
Everything is still on their profile too: invoices, appointments, pets, notes and documents.
Their pets are archived with them, and vaccination reminders stop for those pets.
They still get bulletins and messages you send to all your clients.

Tap the menu button on Home, then Archive > Archived clients. Or search Clients and choose Archived.
Open the client, tap ... and choose Unarchive.

Their pets stay archived. Unarchive each one from Menu > Archive > Archived pets.

Archiving never hides invoices. If an invoice is missing from the Invoices tab, check whether it's under Unpaid or Paid, and that it was created. An automated invoice only appears when its schedule creates it.
Archiving doesn't cancel their future appointments or pause their automated invoices. To stop those, cancel the appointments and pause the automated invoice from Invoices > Automated.
On the free plan, archived clients still count towards your 4 clients. Deleting a client frees up a space, but can't be undone.