When you publish your Website, you are pushing live all the content you have customised to your public URL. Visitors will be able to view your content on all three devices: desktop, tablet and mobile.
To Publish or Republish your website click the Publish/Republish button in the top bar.
Things to consider
After publishing your Website, you will still be able to make edits whenever necessary. Changes to the Website will not be seen until the Website is republished. Remember to republish your Website after any major changes are made.