Full Mac keyboard shortcuts list: https://support.apple.com/en-us/HT201236
Copy: Command + C
Paste: Command + V
Paste without formatting: Option + Shift + Command + V
Cut: Command + X
Undo: Command + Z
Select All: Command + A
Find: Command + F
Save: Command + S
Print: Command + P
New Tab: Command + T (used mostly in web browsers)
Open: Command + O (use to open a file in Word/Powerpoint/Excel)
New Window: Command + N
Screen capture: Shift + Command + 4, then drag a box around what you want to screenshot
Bold: Command + B
Italics: Command + I
Underline: Command + U
Select a file in Finder or on your Desktop, then you can use the following shortcuts:
Rename: Enter
Preview: Space
Delete File: Command + Delete