Enable notifications in a Slack channel:

Integrations → Apps → Add an App

Add Approvals by Approveit

Now when you create/edit the workflow you can specify the channel where you want to post the approval requests: 

If you leave the field blank - a requester can choose the channel himself when he is creating a request

When a requestor creates an approval request, it will be posted in the chosen channel: 

That's it! ⚡️

If you have any additional questions, contact us right away.