10 important keyboard shortcuts in Mac

option + command + space = To open finder

command + space = spotlight

command + shift + 4 = screenshot

Shift + Command + N: Create a new folder.

Shift + Command + Delete = Move selected file or folder to trash

Command + q = immediate quit current app

Command + Left Arrow = Move the insertion point to the beginning of the current line.

Command + Shift + i (in safari) = Send current page link to mail 

Command + Option (in Safari)+ L = Downloads folder

refer for detailed MacBook shortcuts