Basic Text Formatting:
Bold: Ctrl + B
Italic: Ctrl + I
Underline: Ctrl + U
Strikethrough: Ctrl + Shift + X
Superscript: Ctrl + Shift + =
Subscript: Ctrl + =
Paragraph Formatting:
Align Left: Ctrl + L
Align Center: Ctrl + E
Align Right: Ctrl + R
Justify: Ctrl + J
Increase Indent: Ctrl + M
Decrease Indent: Ctrl + Shift + M
Navigation:
Move to beginning of line: Home
Move to end of line: End
Move one word to the left: Ctrl + Left arrow
Move one word to the right: Ctrl + Right arrow
Move to beginning of document: Ctrl + Home
Move to end of document: Ctrl + End
Selection:
Select word: Double-click on the word
Select sentence: Ctrl + Click within the sentence
Select paragraph: Triple-click within the paragraph
Select all: Ctrl + A
Editing:
Cut: Ctrl + X
Copy: Ctrl + C
Paste: Ctrl + V
Undo: Ctrl + Z
Redo: Ctrl + Y
View and Navigation:
Switch to Print Layout view: Alt + Ctrl + P
Switch to Full Screen view: Alt + Ctrl + F
Zoom In: Ctrl + [
Zoom Out: Ctrl + ]
Review and Collaboration:
Spell Check: F7
Track Changes: Ctrl + Shift + E
Insert Comment: Ctrl + Alt + M
Miscellaneous:
Find: Ctrl + F
Replace: Ctrl + H
Insert Hyperlink: Ctrl + K
Insert Page Break: Ctrl + Enter
Insert Symbol: Alt + Numpad code
These are just a few shortcuts. Word offers many more, and you can even customize your own shortcuts in Word's options menu.