How to Insert a Comment in Google Docs (Ctrl+Alt+M)

Selecting a piece of text and pressing Ctrl+Alt+M (Cmd+Option+M on Mac) attaches a comment to that specific selection, opening a small text box in the right-hand margin ready for typing a note without proposing any actual change to the underlying content. **How comments differ from Suggesting mode**: a comment is purely a note about the selected text — asking a question, flagging a concern, or leaving context — with no effect on the document's actual content. Suggesting mode, by contrast, proposes an actual edit shown as colored inline markup. The two are frequently combined: a suggested change accompanied by a comment explaining the reasoning behind it, giving a reviewer both the proposed edit and the rationale in one place. **@mentioning a specific collaborator**: typing @ followed by someone's name or email address inside a comment triggers an autocomplete and, once selected, sends that person a direct notification (typically by email) alerting them specifically to the comment, distinct from a general comment that any collaborator might eventually notice on their own while reviewing the document — useful for directing a specific question at the one person who can actually answer it rather than hoping they happen to check back. **Threaded replies**: any collaborator with comment access can reply directly within an existing comment thread rather than starting a new, separate comment on the same or nearby text, keeping a back-and-forth discussion about one specific point contained and organized rather than scattered across several disconnected comments on the same area of the document. **Resolving a comment**: once a comment's concern has been addressed — either through direct conversation in the thread or an accompanying edit — pressing Ctrl+Enter with that comment focused (or clicking its Resolve button) marks the thread as resolved, removing it from the active margin view while still preserving the full thread in the resolved-comments history for later reference if needed. **Where comments attach**: a comment is tied to the specific text selection it was created on, and if that underlying text is later edited or deleted, the comment generally persists but may shift position or, in cases of significant surrounding changes, become slightly detached from its original precise anchor point. **Related shortcuts**: Ctrl+Alt+Shift+A opens a consolidated panel listing every comment across the whole document at once; Ctrl+Alt+N and Ctrl+Alt+P step sequentially forward and backward between individual comment markers. **Mistake to avoid**: using a comment to propose an actual text change (writing "change this to X" as a comment rather than actually making the edit) instead of switching to Suggesting mode and making the edit directly as a trackable, one-click-acceptable suggestion — the comment-only approach requires the document owner to manually find, read, and then separately implement the suggested wording themselves, which is considerably more friction than reviewing and accepting an actual suggested edit with a single click. **Attaching a comment without selecting text first**: it's possible to add a comment with the cursor simply placed at a point in the document rather than an actual text selection highlighted, which anchors the comment to that approximate location rather than to a specific span of text — generally less precise than selecting the exact relevant phrase first, since a location-anchored comment can become ambiguous about exactly what it was referring to once surrounding text shifts from later edits. **Comments on non-text elements**: comments aren't limited to selected text alone — an inserted image, table, or other embedded object can also be commented on directly by clicking it first and then applying the same comment shortcut or toolbar action, which is useful for feedback specifically about a chart, image, or table rather than the surrounding prose.