Not getting checkout page settings option in pabbly subscription

I am trying to customize the checkout page but I am not getting that option. Please find attached a screenshot for reference.

Also please suggest how to add a custom thank you page so that I can redirect people to the thank you page after making a successful payment.

Hello Sneha,

Please follow the path : Products >> Edit plan menu (3dots menu) >>Checkout Customizer. Please find attached a screenshot for reference.

For Redirect URL, go to "Edit Plan Section". There you will find the option to put redirect URL. Please refer image2.