This website https://learn.microsoft.com/en-us/visualstudio/vsto/deploying-a-vsto-solution-by-using-windows-installer?view=vs-2022#to-build-the-setup-project is a pretty comprehensive guide to creating msi installers for vsto addins. HOWEVER, if you are using Visual Studio 2022 the guidance is out of date because the default is for solutions to use embedded PIAs. This means that the two launch conditions: 'Search for Office Shared PIA' and 'Verify Office 2010 Shared PIA availability' are not required. If they are included it is likely that the third party machine will not have them and give an error message. Somebody should ask Microsoft to update this guidance. (I only spent 2 frustrating days in working this out)