You'll want to trigger the Pyspark job via an Action, which lets you generate and send an email notification as a side effect. Check out the docs here.

In principle you could hit a 3rd party API like SendGrid to send the email, although you lose some of Palantir's data security guarantees this way. To do it this way would require getting egress to the email provider whitelisted, creating a Data Connection to that provider, and then using that to send the request.