If the express payment buttons are not showing up on your checkout page, then please make sure to meet the guidelines of respective payment providers.
Apple Pay
You can enable the Apple Pay button on the Checkout page in your web browser. There is no additional configuration required to enable Apple Pay on the web.
Your website must have a valid and active SSL certificate installed.
Your device must be compatible with Apple Pay - see the complete list.
Check the full list of countries and regions that supports Apple Pay.
Ensure that your domain should be verified.
Ensure that your customer is using the Safari web browser.
Google Pay
There is no additional configuration required when enabling the Google Pay button via Stripe on your web browser.
Ensure that your customers are using the Google Chrome web browser.