
Magento 2 default page, which is appeared as Home Page, once user typing URL & specified URL page found as “Page Not Found” error occurs, the default page will be displayed.
Finally, Magento 2 Home Page & Error Page “Page Not Found” defined as Default Pages.
There are following below steps to follow to configure Default Pages.
[1]- Go To STORES > Configuration, redirects on configuration.

[2]- Left Panel Clicked on General > Web, redirects on [Right Panel]

[3]- Once redirection on [Right Panel]

[4]- Once clicked / expanded, Default Pages [Right Panel]

Each Input Field of Default Pages defined as below
[4.1]- Default Web URL : By Default cms or enter other value as per Store Requirement.
[4.2]- CMS Home Page : By Default Home Page selected or select other page from drop as per Store Requirement.
[4.3]- Default No-route URL : By Default “cms/index/noRoute” or enter other value as per Store Requirement.
[4.4]- CMS No Cookies Page : By Default “404 Page Not Found” selected or select other page from drop as per Store Requirement.
[4.5]- CMS No Cookies Page : By Default “Enable Cookies” selected or select other value from drop as per Store Requirement.
[4.6]- Show Breadcrumbs for CMS Pages : By Default “Yes” selected, if do not want display Breadcrumbs for CMS Pages, select No.
[5]- Finally click on Save Config Button