a) You can submit your subscription code on the Odoo Enterprise website (https://www.odoo.com/enterprise/) by logging into your account and going to the "Subscriptions" section. There you will find a form to enter the subscription code and activate the license for your on-premise installation.

b) If the "Register your subscription" message is not appearing on your production database after upgrading the 'web_enterprise' module, it could be caused by several reasons:

• The subscription code is not being applied to the correct database: Make sure that you are applying the subscription code to the correct database and that the database you are upgrading is the same one that you are registering the subscription code for.
• The subscription code has been already registered: Double-check that the subscription code has not already been registered and that the license is already activated for that specific database.
• The subscription code is incorrect: Make sure that you are entering the correct subscription code and that it has not expired.
• The subscription code is blocked: if the subscription code is blocked by Odoo because of a violation of the terms of use, you need to contact Odoo Enterprise Support to request reactivating it.

If you've checked all the above possibilities and the issue persists, you can contact the Odoo Enterprise Support for further assistance in resolving the issue. They will be able to check the status of your subscription code and help you activate it properly.

I am facing same issue, can anyone advice on this?