Why the widgets Do not come on the home page on ipad

iPadOS14 (for iPad) differs from iOS14 (for iPhone) in that you can always have the Today View and Widgets “pinned” to your first Home Screen. By contrast, for iPhone, you can freely place Widgets on your Home screens.

To conclude, the iPad and iPhone have different capabilities and features. For iPad, you do not have the facility to freely place Widgets throughout your Home Screens.

Use widgets on your iPad - Apple Support

Because they don't work that way in iPadOS. You cannot add widgets to the home screens and there is no app library. You can add widgets to the Today view side bar on the first home screen.