Let's say you created a page and you named it "home", but you want this page to be your homepage, meaning when you visit your site's main domain (ex: site.com) you want that page to show up.
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This is a standard functionality in WordPress and all you need to do is going to your WordPress Dashboard => Settings => Reading.
From here you can select the homepage of your site as seen in this screenshot:

​Note: Do not select a page as your "Posts Page" if you using the Divi builder to create it, as the Divi builder will be disabled.