GOOGLE SHEET cell data linking

To make a link to ONE cell on another sheet (within the same spreadsheet file) in GOOGLE SHEET :

*  =SheetName!A1

*  ='Long Sheet Name'!A1


For a range (MORE THAN ONE) of cells :

=arrayformula('Long Sheet Name'!A1:C4)

For the whole columns :

=arrayformula('Long Sheet Name'!A4:C)

For the whole rows :

=arrayformula('Long Sheet Name'!A3:4)

Make sure that the target cells are empty when using =arrayformula, or it will give out error message.

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To make a link to a cell or a range of cell on ANOTHER file,  use =ImportRange function.

*  =ImportRange("file key";"Sheet Name!A1")