The Billing Address to be displayed under the Each Payment method Section by default in Magento 2.
You can manage Billing Address on the Payment page after the Payment Method section or Below all the Payment method section.
Its Setting Configuration from the admin panel to manage the payment method on the Checkout page.
Login with Admin panel,
1. Click on Stores -> Configuration -> Sales -> Checkout.
2. From the Checkout Options -> Display Billing Address On the dropdown field.
3. Choose Payment Page value
4. Click on Save Config.
5. Clear the Cache by CLI or from admin panel Cache Management.
Go To Frontend, Add Items to cart, click on Checkout button from the Minicart, Check the Payment and Review step,
Your Billing Address Section will be displayed after the payment methods.
This is the OOTB Setting to display the Billing address on the checkout page.
If you have a custom requirement to display billing address before the payment methods check the link, Display Billing address before all the Payment methods.