Lotus 1-2-3 Converter is a Windows desktop application. Use a Windows 10 or 11 PC to download and install the offline MSI.
If you are visiting from Mac, Linux, iOS, or Android, move to a Windows 10 or 11 computer before downloading the installer.
Download the offline MSI from this site. It installs the full app and includes the free trial (up to 10 Lotus files). The MSI is useful for air-gapped or scripted installs.