Referencing Cells on Other Sheets
To reference a cell on another sheet, input the sheet's name within single quotes, followed by an exclamation mark, and then the cell reference (or cell range).
For example, for cell A1 on "Sheet 2":
='Sheet 2'!A1
If the sheet name does not contain spaces, the single quotes are not needed:
=Sheet2!A1
Usage
In most cases, you don't need to type it manually because you can simply enter an =
and then click directly on the cell or cell range on the other sheet: