Why is my document annotation button disabled?

If the document annotation button is disabled in ForeFlight Mobile, it's likely due to the document's permissions settings, which control who can view, share, edit, and annotate the document. Since ForeFlight Mobile respects these setting, the annotation button will be disabled if annotations are disallowed.

To enable annotations, the document owner needs to adjust the annotation permissions using a PDF editor that supports permission changes (e.g., Apple’s Preview). For example using Apple Preview, go to File > Edit Permissions to adjust settings. A password may be required to make changes.