Click the cell where you want the total to appear
Type `=SUM(`
Select the column range you want to add, such as `A1:A10`
Type `)` and press Enter
Use `=SUM(A:A)` to add the entire column
Use AutoSum by selecting the total cell and pressing `Alt` + `=` on Windows or `Command` + `Shift` + `T` on Mac
Copy the formula to other cells if needed