How can I set a page to only receive data from the specified page post?

If the user registration information is verified on the frontend, can you set some settings on the page for receiving data to only receive data on the specified page. How to Set it? Another problem is: Can I not perform backend verification if I have limited the number of data sent from a page? If the user registration information is verified on the frontend, can you set some settings on the page for receiving data to only receive data on the specified page.
How to Set it?

Another problem is: Can I not perform backend verification if I have limited the number of data sent from a page?

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If the user registration information is verified on the frontend, can you set some settings on the page for receiving data to only receive data on the specified page.
How to Set it?

Another problem is: Can I not perform backend verification if I have limited the number of data sent from a page?

The front-end uses verification information + Page Information encryption, and post the information to the backend for backend decryption. After decryption, analyze whether the information is valid.

The backend must be verified and never trust the data sent from the client.

Pass a variable to the backend to determine if the variable is correct