The greyed-out files are not supported.
The following file types are currently supported:
- Image (via the Import Image function)
- Word (.doc, .docx) and PowerPoint (.ppt, .pptx)
- GoodNotes (.goodnotes)
- GoodNotes backup (.goodnotes.zip)
To import a non-supported file, like Excel, convert it to PDF first and import that PDF into GoodNotes:
1. Open that file on your iPad. For example, if the file's in iCloud Drive, you can open it there.
2. Tap the Export button > Print (or a similar function in the external app).
3. Spread with 2 fingers over the Print Preview panel.
4. Tap the Export button > Open in GoodNotes or Copy to GoodNotes.