Yes, you can add a webhook source to a table in Clay that doesn't already have one. To do this, open the table you want to use, click on the "Action" button, select "Import," and then choose "Monitor Webhook" or "Import Data from Webhook." Clay will generate a unique webhook URL for that table, which you can then use to send data from external sources directly into your table. This process works for both new and existing tables that do not yet have a webhook source configured.