Here is what I can currently see under the Tax Report screen, from a company with the generic localisation package applied.

Here is the screen I can see under the Accounting>Tax Returns screen:

You seem to be looking for the revamped version of Accounting -> Accounting --> Closing -> Tax Returns.

In there, you should find a listing like below where Odoo has pre-created the report records already (Note: I'm not having any in-use 18.3+ environment at hand, thus using the runbot. In there, due to the nature of the demo data, I first had to set the Accounting Period's Opening Date). Once a return is in Submit state, you will be able to download the actual Returns PDF (paperclip icon) and view the actual Entry (as you would have seen it previously). Then, finally you would just Pay it.

To reassure yourself you may play around in https://demo.odoo.com (18.4) or any https://runbot.odoo.com environment (USR/PWD: admin) to see what happens once you start the Tax Return process.

View Entry:

Open Attachments:

->

You should be able to find the Entries from the Accounting ->Dashboard -> Tax Returns kanban as well:

Likely Causes & Fixes:

1. User Access Rights:
   • Ensure your user has Accounting > Advisor access rights.
   • The button is hidden for lower access roles like Billing or Accountant.
2. Fiscal Localization Missing or Misconfigured:
   • Make sure the correct fiscal localization package (e.g., for your country like l10n_in, l10n_de) is installed.
   • Navigate to Accounting > Configuration > Settings and confirm the correct localization is selected.
3. Fiscal Year Settings:
   • If fiscal years are not defined or closed already, the button may disappear.
   • Go to Accounting > Configuration > Fiscal Years and check if the year is set up and open.
4. Module Updates:
   • If the system was recently updated, this button might be hidden due to a change in view or conditional logic in the latest patch.
   • Try upgrading the account module or rechecking custom views.
5. Menu Path:
   • It may have moved. Try navigating to:
     Accounting > Reporting > Tax Report → Look for "Close Period" or "Generate VAT Entry" there.