Select the cell and click in the formula bar
Highlight the specific character you want to format as superscript
Press Ctrl+1 to open Format Cells
Go to the Font tab
Check Superscript
Click OK
If needed, repeat for other characters in the cell
Select the cell and click in the formula bar
Highlight the specific character you want to format as superscript
Press Ctrl+1 to open Format Cells
Go to the Font tab
Check Superscript
Click OK
If needed, repeat for other characters in the cell