If you have subscribed to one or more MT services, you can set those up in the Intento plugin. This way, you will pay for each service provider separately.
If you have not set up a Connected Account yet, you can do this in the Intento console https://console.inten.to/accounts or click the link in the plugin form:
Choose the required Credential ID or choose via Intento if you prefer to use Intento accounts to access the provider
Press Test and save on Configure Machine Translation form.