HubSpot can be used as:
When working with lead flows, you can new create new Contact in your HubSpot account and add them to a static list. New contacts can also be created when pushing the lead as a form submission in your HubSpot account. When working with audience flows, you can pull Contacts in your static or dynamic lists.
Connecting your HubSpot account with Ads Workbench is really simple. You just need to follow these steps:
A lead flow is an automation that allows you to collect the leads coming from a source and send them to multiple destinations. Once your ad account is connected and your have created the integrations for the systems where the leads will be sent, you can create you lead flow as described in the following video:
An audience flow is an automation that allows you to keep fresh your custom audiences using as an input your subscribers' or contacts' data. Once your ad account is connected and your have created the integrations for the systems where your contacts' data is stored you can create you audience flow as described in the following video: