Insert/edit comment

`Ctrl` + `Alt` + `M`

All hotkeys for Google Sheets (Android)

Common actions Select column	`Ctrl` + `Space`
Common actions Select row	`↑ Shift` + `Space`
Common actions Select all	`Ctrl` + `A`
Common actions Space	`Ctrl` + `↑ Shift` +
Common actions Undo	`Ctrl` + `Z`
Common actions Redo	`Ctrl` + `Y`
Common actions Redo	`Ctrl` + `↑ Shift` + `Z`
Common actions Find	`Ctrl` + `F`
Common actions Find and replace	`Ctrl` + `H`
Common actions Fill range	`Ctrl` + `⤶ Enter`
Common actions Fill down	`Ctrl` + `D`
Common actions Fill right	`Ctrl` + `R`
Common actions Print	`Ctrl` + `P`
Common actions Copy	`Ctrl` + `C`
Common actions Cut	`Ctrl` + `X`
Common actions Paste	`Ctrl` + `V`
Common actions Paste values only	`Ctrl` + `↑ Shift` + `V`
Common actions Paste format only	`Ctrl` + `Alt` + `V`
Common actions Show common keyboard shortcuts	`Ctrl` + `/`
Common actions Insert new sheet	`Ctrl` + `T`
Common actions Move to sheet at index #	`Ctrl` + `1` - `9`
Format cells Bold	`Ctrl` + `B`
Format cells Underline	`Ctrl` + `U`
Format cells Italic	`Ctrl` + `I`
Format cells Strikethrough	`Alt` + `↑ Shift` + `5`
Format cells Center align	`Ctrl` + `↑ Shift` + `E`
Format cells Left align	`Ctrl` + `↑ Shift` + `L`
Format cells Right align	`Ctrl` + `↑ Shift` + `R`
Format cells Apply top border	`Alt` + `↑ Shift` + `1`
Format cells Apply right border	`Alt` + `↑ Shift` + `2`
Format cells Apply bottom border	`Alt` + `↑ Shift` + `3`
Format cells Apply left border	`Alt` + `↑ Shift` + `4`
Format cells Remove borders	`Alt` + `↑ Shift` + `6`
Format cells Apply outer border	`Alt` + `↑ Shift` + `7`
Format cells Insert link	`Ctrl` + `K`
Format cells Insert time	`Ctrl` + `↑ Shift` + `;`
Format cells Insert date	`Ctrl` + `;`
Format cells Format as automatic	`Ctrl` + `↑ Shift` + `'`
Format cells Format as decimal	`Ctrl` + `↑ Shift` + `1`
Format cells Format as time	`Ctrl` + `↑ Shift` + `2`
Format cells Format as date	`Ctrl` + `↑ Shift` + `3`
Format cells Format as currency	`Ctrl` + `↑ Shift` + `4`
Format cells Format as percentage	`Ctrl` + `↑ Shift` + `5`
Format cells Format as exponent	`Ctrl` + `↑ Shift` + `6`
Format cells Clear formatting	`Ctrl` + `\`
Format cells (with columns selected) Insert columns	`Ctrl` + `Alt` + `=`
Format cells (with columns selected) Insert columns	`Ctrl` + `Alt` + `↑ Shift` + `=`
Format cells (with columns selected) Delete columns	`Ctrl` + `Alt` + `-`
Navigating spreadsheet Move to section boundary	`Ctrl` + `← ↑ → ↓`
Navigating spreadsheet Select from current position to section boundary	`Ctrl` + `↑ Shift` + `← ↑ → ↓`
Navigating spreadsheet Scroll to active cell	`Ctrl` + `⬅ Backspace`
Navigating spreadsheet Move to next sheet	`Ctrl` + `⭾ Tab`
Navigating spreadsheet Move to previous sheet	`Ctrl` + `↑ Shift` + `⭾ Tab`
Navigating spreadsheet Display list of sheets	`Alt` + `↑ Shift` + `K`
Navigating spreadsheet Open hyperlink	`Alt` + `⤶ Enter`
Navigating spreadsheet Open Explore	`Alt` + `↑ Shift` + `X`
Editing notes and comments Insert/edit note	`↑ Shift` + `F2`
Editing notes and comments Insert/edit comment	`Ctrl` + `Alt` + `M`
Editing notes and comments Open comment discussion thread	`Ctrl` + `Alt` + `↑ Shift` + `A`
Open a menu (in Google Chrome) Insert menu	`Alt` + `I`
Open a menu (in other browsers) Insert menu	`Alt` + `↑ Shift` + `I`
Open a menu (in Google Chrome'da) Format menu	`Alt` + `O`
Open a menu (in other browsers) Format menu	`Alt` + `↑ Shift` + `O`
Open a menu Sheet menu (copy, delete, and other sheet actions)	`Alt` + `↑ Shift` + `S`
Open a menu Context menu	`Ctrl` + `↑ Shift` + `\`