reuse: add annotate example (#16543)

Co-authored-by: Managor <42655600+Managor@users.noreply.github.com>

pages/common/reuse.md

@@ -11,6 +11,14 @@
 
 `reuse --root {{path/to/directory}} lint`
 
+- Add copyright statement to file:
+
+`reuse annotate {{[-c|--copyright]}} "{{your_name}} <{{your_email}}>" --fallback-dot-license {{path/to/file}}`
+
+- Add licence information to file:
+
+`reuse annotate {{[-l|--license]}} {{spdx_identifier}} --fallback-dot-license {{path/to/file}}`
+
 - Download a license by its SPDX identifier and place it in the LICENSES directory:
 
 `reuse download {{spdx-identifier}}`