Activation and usage

To activate the functionality, in Settings - Your company, enter the tax number of the foreign company (without country code) 

On the individual retail invoice, adding appropriate label is needed:

The same can be indicated on the credit notes

If such an invoice is also issued, the tax identification number under which the invoice has been issued will be displayed in the "More information" section (see the picture below).

FAQ

When issuing the invoice, ''Issuing in the foreign name'' was not turned on. May I activate it and reprint the invoice?

No. Since the invoice was already sent to FURS, a credit note needs to be issued or invoice needs to be canceled and reissued.

The new tax number has been entered/changed in Your Company. Is that going to have an impact on already issued invoices?

No. Tax number is recorded on the invoice/credit note after the first time you save the invoice. If later on tax number is changed in Settings, that will not have an impact on the existing invoices that have been already issued. Consequently, the tax number cannot be changed on the already issued invoices.