The personal access token comes from the developer portal
You generate the token a Shopier connection needs by opening an account on a separate developer portal, not in your seller panel. Not finding it in the panel is normal. The token is a personal access token and is enough on its own to establish the connection.
The second field, the webhook signature token, works on a different logic: you do not generate it — it comes back inside the response when the webhook subscription is created. So the order matters: subscription first, token second.