General use case

Notify slack of the results of a single job run.

- uses: 8398a7/action-slack@v3
status: ${{ job.status }}
fields: repo,message,commit,author,action,eventName,ref,workflow,job,took # selectable (default: repo,message)
GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # optional
SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }} # required
if: always() # Pick up events even if the job fails or is canceled.

status: ${{ job.status }} allows a job to succeed, fail or cancel etc. to action-slack.
if: always() to trigger action-slack even if the job fails Let them.

For the fields, look at Fields to determine what you want.