Press and hold the Option key
Press the Delete key while holding Option
Use Option + Backspace to delete the previous word in many apps
Use Command + Delete to move the selected item to the Trash
Use Option + Command + Delete to delete a word to the left in some text fields
Use Control + Option + Delete only if a specific app or shortcut requires it
Check System Settings > Keyboard > Keyboard Shortcuts for custom key mappings
Use an external keyboard if the Mac keyboard layout makes the shortcut unclear