There are two ways to do this:
1. Use the Ezoic tool on a page you want to update. Go to the page you want to update and press 'ctrl / alt / e' all 3 buttons at the same time (on a mac - don't default to the Cmd button, use Control + alt (Option + fn) + e). Look for a toolbar button to appear at the bottom of the page and click on the 'clear cache' button; which will force the content to refresh to all users.
2. Set up a caching rule (if you update one page on your site regularly). See 'updating content' article for more details.