You will need to verify that your client is registered as European Trader in order to issue your invoice without VAT/IVA to them.
You need to include your client’s VAT number in your invoice.
Remember that you have the obligation to report to Tax Authorities information of your clients or suppliers with whom you exchanged intra-communitarian operations. Make your that you collect correctly the tax information of these in order to be include in the recapitulative statement. (modelo 349).
1. DO I HAVE TO BE REGISTERED AS EU TRADER TO VERIFY A NUMBER?
NO, But you will have to introduce a valid NIF /VAT number as the requester. Your Spanish VAT number ( or your NIE) is sufficient.
2. WHAT IF MY CLIENT IS NOT REGISTERED?
If you get an “invalid” number, after proper verification with your client that the number given is right, you will not be able to issue an invoice without IVA. Doing so can bring you a fine from tax office.
3. IN WHAT CASES DO I HAVE TO BE REGISTERED?
Check our article: European VAT number and Intra-Community Invoice