IMVU only needs XMF, XSF, XAF and XPF files. The default settings should generally be fine for IMVU. Choose a location where the files should be saved and press the button called Export Cal3d for IMVU ...
Installing IMVU Toolkit for Blender in Blender 4.0+ on MacOS More info https://www.katsbits.com/codex/macos-imvu-toolkit-blender-4/ ...