By default, when you press the "Enter" key on a spreadsheet, you will move the highlighted cell to the one below it. Use the Alt key to insert new lines into the same cell in a column. If a cell has multiple lines of data and you want to see all of it at once, you may either resize the row height to fit the data, or click the down arrows to the right of the formula bar to expand it.
Type something into a cell on your Excel spreadsheet.
Press and hold the "Alt" key.
Press "Enter." Excel inserts a line break into the cell and you may type more data.