Short answer
HubSpot's KB: CSAT surveys can be sent by email or chat, or shown on a page with the tracking code. After closing a chat, the survey can be sent in the chat widget. Their workflows don't appear in the workflows tool; edit them in the survey setup. Reminder emails aren't supported for CSAT.
1. Surveys
Feedback surveys in my demo portal.

2. NPS
See NPS surveys.