On the desktop and in Windows Explorer, the entry “Ask Copilot” has been appearing in the context menu when right-clicking on a registered file type such as DOCX, TXT, PDF or PNG for a few weeks now.
Press Windows + I to open Settings. Go to Apps > Installed Apps. In the search bar, type Cortana. When Cortana appears in the list, click the three-dot menu beside it. Select Uninstall and confirm ...