Find the "billing software" column and click "VAT invoice billing software (tax UKey version)" to download it (as shown below).
Save it to the computer desktop (you can download the "VAT electronic invoice format file reader" as required). Unzip the installation package, double-click to run the installation, click Install Now, and follow the prompts until the installation is complete. A shortcut to the "ticket" icon of the billing software is generated on the desktop, which means that the VAT invoice billing software (tax UKey version) has been successfully installed.