Complete passport copies are requiredI am not a senior member of this forum but here's my two cents anyway: I don't think a full passport is necessary for online applications and they never asked for it anyway. But since they gave an option to attach additional documents, I uploaded a full copy there. Sometimes when they want to check all visa stamps or other entry exit details on the passport, they want to look at all pages. Again, nothing to be alarmed in my view.
https://www.canada.ca/en/immigration-refugees-citizenship/services/application/application-forms-guides/guide-0002-application-canadian-citizenship-under-subsection-5-1-adults-18-years-older.html