A good place to start.

Yes. Companion is a client for an existing Kimai server. It does not provide a hosted Kimai account. Ask your organisation's administrator for your server address, or visit Kimai to learn about its time-tracking platform.

You can connect your first account and view your time without a subscription. An annual subscription enables starting timers, creating, editing and deleting entries, and adding more accounts. You can always stop a running timer. Existing saved accounts remain readable if your subscription expires.

Open Settings, then Subscription, to restore purchases or manage your subscription. Apple manages purchases, billing and cancellation. You can also manage subscriptions with Apple. Sign in to the Apple Account you used for the purchase.

Companion checks running timers while the app is active, and refreshes when you return to it. iPhone and iPad do not continuously refresh in the background. On Mac, menu-bar monitoring can keep running when the window is closed. Check your connection and use Refresh if you need to update immediately.

With an active subscription, open Settings, Manage Accounts, then Add account. The account switcher changes the account you're viewing. Switching accounts does not stop the other account's timers.

Companion needs a connection to your Kimai server to load and save entries. Offline editing and synchronisation are not currently supported.

This optional account setting can combine time from a restarted timer with its original entry. It needs a compatible custom field on your Kimai server and is off by default. Read the in-app setup instructions before enabling it; the resulting entry does not preserve the break between sessions.

Open Settings, Manage Accounts, choose the account, then remove it. This removes its saved login from the device; it does not delete the account or timesheets on your Kimai server, or stop timers there. You can revoke the API token separately in Kimai.