You can sync columns from your source to Customer.io's fields. Customer.io does not provide info about existing fields, so you will have to type the names of the fields inside.
You can choose what Hightouch's behavior is when records leave the query result set. The default is doing nothing, but you can also set Hightouch to delete the Customer.io customer on record exit.
Hightouch allows you to pass data to the event properties of a Customer.io event. If a field doesn't exist, Hightouch will automatically create the field within Customer.io.
Segment mode syncs a query result to a Customer.io segment. Segments are automatically created in Customer.io based on the name of the query, and each query can sync to only one segment.
Hightouch adds and removes users to a segment as records are added and removed in the query results.