General Use Case

Notify slack of the results of a single job run.

steps:
  - uses: h3y6e/action-slack@v4
    with:
      status: ${{ job.status }}
      fields: repo,message,commit,author,action,eventName,ref,workflow,job,took,pullRequest # selectable (default: repo,commit)
    env:
      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.

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