So I add an element to the page or a new product, I hit the “save” button, and when I enter the website, it shows the old version and it doesn’t update
It would be better if you would have shared the url to your store so that we can see what theme you are using and if your theme is the culprit here.
But, this may also be a cache issue on your device. For example, if you are accessing your website from a chrome browser on a computer then you may have to hard reset the cache to see the updated version of the website. At times some corrupt cookies installed in the browsers are the reasons behind this issue.
Below are instructions for doing a “hard reload” for Chrome, Firefox, and Internet Explorer.
Chrome, Firefox, Edge, and related browsers:
A quick hard reload can be done by using the following shortcut keys
On Windows/Linux:
Hold down Ctrl and click the Reload button.
Or, Hold down Ctrl and press F5.
Or just open the Chrome Dev Tools by pressing F12 (or right click Inspect). Once the Chrome dev tools are open, right-click on the reload button, and a menu will drop down. Click on “Empty Cache and Hard Reload