How to transfer from a Standard page to a Homepage?
Creating a page with the wrong page type is a problem usually committed by EComposer users. For example, you created the Homepage under the Standard page by mistake. So you might want to switch from the Standard page to the Homepage instead of recreating the page from scratch.
The way to solve it is to save your page as a template first, and then you can insert it from the My Templates tab into any page type you want. Similar to when you want to switch between different page types.
Finally, please click Save the page and tick the Publish and Overwrite Shopify default homepage options.