The original contract is required for the extension of the enterprise's foreign debt business. According to the relevant public information, the extension of enterprise's foreign debt business should be registered with the foreign exchange bureau with the extension application, the original extension contract, the original foreign debt signing, the copy of business license and the approval certificate. According to the relevant operating instructions of the electronic tax bureau, taxpayers can log in to the electronic tax bureau with their real names, and then apply for an extension of cross-regional tax-related matters through the cross-regional tax-related matters management package business module (operated by other provinces in this city).