Most of our software products are offered in two editions: Installer and Portable
Installer is an application packaged into an installation program (setup wizard). The installer places the application into a specific folder, customarily into "Program Files (x86)", creates shortcuts and adds an uninstaller. The installer may also register file associations and extra components in the system to enable additional functionality of the application. Installer usually requires administrator privileges.
Vovsoft installers are created using Inno Setup. It is an open-source setup creator for Windows programs. NSIS (Nullsoft Scriptable Install System) is also a good alternative.
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Portable application can be placed in any folder on your computer, a USB flash drive or other removable media and launched from there. Portable software creates configuration files in its folder and generally doesn’t change anything in the system it runs on. If you copy the configuration files together with the executable file to another media, all your settings will be carried across too.
Unless you have specific reasons to use the portable edition, it is best to use the installer to get the best of what the software has to offer.
Installed applications don't have access to write in the Program Files directory. So, they usually store their settings and temporary files in the AppData folder.
Example:
Portable programs, on the other hand, don't use the AppData folder. They use the folder of the main executable file.
⚠️ An important detail to note here is that if you run an installed program with administrator privileges, it gains the ability to write to the Program Files folder. Therefore, when run as administrator, it can write its settings and temporary files to its folder inside Program Files.