Use the Add to Slack action to push messages from a WordPress form to Slack. You can configure the message text and use WS Form variables in message settings.
The Slack premium integration supports message color, attachment titles, images, icons, buttons, and field mapping. Messages can be posted to public and private channels in your workspace.
WS Form can also create a Slack form automatically so it is pre-configured to push messages to one of your Slack channels. If you use a private channel, add WS Form as an app to that channel first.