echo "your_admin_psw" | sudo -S installer -pkg ~/Downloads/FoxitPDFEditor1100.L10N.Setup.pkg -target /
Type admin password without the ""
Use the Foxit macOS Customization Wizard tool to inject the license (fpmmkey.text) into the PKG as well as make Foxit PDF Editor the default PDF software. Here's how to do that: macOS Customization Wizard Tool