https://docs.magento.com/m2/ce/user_guide/cms/page-home-new.html

Switching Home Pages

You can maintain a selection of different home pages, and activate the page that you want to use as the default home page.

異なるホームページをメンテして、標準のページを有効にすることができます。

To Change the Home Page:

1. Complete the steps to add a new page.
2. On the Admin sidebar, tap Stores. Then under Settings, choose Configuration.
3. In the panel on the left under General, choose Web.
4. Expand the Default Pages section. Then, do the following:

Default Pages
a. Set CMS Home Page to the new page.
b. Tap Save Config.
5. In the message at the top of the workspace, tap the Cache Management link, and refresh any invalid caches.