Google Sheets (iPhone & iPad)

General

Underline

⌘ Cmd + U

All hotkeys for Google Sheets (iPhone & iPad)

General
Bold

⌘ Cmd + B

General
Underline

⌘ Cmd + U

General
Italic

⌘ Cmd + I

General
Strikethrough

⌥ Option + ↑   Shift + 5

Similar combinations for other applications

Cisco Jabber (Mac)
Underlined
Instant messages

⌘ Cmd + U

Adobe Illustrator (Mac)
Show/ hide smart guides
View artwork

⌘ Cmd + U

Ableton Live 10 (Mac)
Quantize
Clip View MIDI Editor

⌘ Cmd + U

QuickBooks Desktop (Mac)
Edit > Transaction History
Editing

⌘ Cmd + U

Confluence (Mac)
Underline
Editor

⌘ Cmd + U

Adobe Lightroom Classic (Mac)
Auto tone
Working in the Develop module

⌘ Cmd + U

Adobe Animate CC (Mac)
Ungroup
Edit and modify

⌘ Cmd + U

Roll20
Add selected object(s) to turn tracker
Tools

⌘ Cmd + U

Adobe Premiere Pro (Mac)
Underline
Titler

⌘ Cmd + U

Corel Painter (Mac)
Ungroup
Layer selection tools

⌘ Cmd + U

CodeMirror
Undo the last change to the selection, or if there are no selection-only changes at the top of the history, undo the last change
General (Mac)

⌘ Cmd + U

AWS Cloud9 IDE (Mac)
Open Tree Panel
Miscellaneous

⌘ Cmd + U

Apple iBooks
Apply underline to selected text
Format text

⌘ Cmd + U

IntelliJ IDEA (macOS)
Go to super-method/ super-class
Navigation

⌘ Cmd + U

Apple Pages
Apply underline to selected text
Formatting text

⌘ Cmd + U

Google Sheets (Mac)
Underline
Format cells

⌘ Cmd + U

iPad Smart Keyboard
Underline
Keynote

⌘ Cmd + U

Visual Studio Code (Mac)
Undo last cursor operation
Multi-cursor and selection

⌘ Cmd + U

Apple macOS
Underline the selected text, or turn underlining on or off
Document shortcuts

⌘ Cmd + U

Xcode
Underline the selected text or turn underlining on or off (equivalent to the Underline command)
Other system and application shortcuts

⌘ Cmd + U

iTunes 11 for Mac
Stream audio file at a specific URL to iTunes
File menu

⌘ Cmd + U