To insert a character at the beginning of a cell without changing its contents, follow these steps:

1. Select the cell where you want to insert the character.
2. Type the character you want to insert at the beginning of the cell.
3. Type the
   Code:

   =CONCATENATE("X",A1)

   function in the formula bar, replacing "X" with the character you want to insert and "A1" with the cell reference of the original cell.
4. Press Enter to apply the formula to the cell.
5. Copy the formula to the rest of the column by dragging the fill handle (the small square at the bottom right corner of the cell) down to the last cell in the column.

This will insert the character at the beginning of each cell in the column without changing the original cell contents.