You generally cannot submit a published article to a publication. So, if it is in draft form: 1) Find the pub you want to submit to. Find their submission guide and folllow instructions to be "added as a writer." Usually, you can ask to be added by leaving a comment on the guide. 2) After you're added as a writer, go to your story and click the three dots next to the publish button. Select Add to Publication, then select the publication. Then, click Publish and then Submit just like you do when publishing to your profile page.

If you've already posted it on your profile page, generally, you're not able to have it published elsewhere. Unfortunately.

Don't I recognize your username from Politically Speaking? I was an editor there before it sunsetted.