If you create or use lists in excel you may want a column with a tick in if to show if something is done. If you are going to use the column for something (other then for printing) such as filtering or Pivot tables, you can add a tick manually.
Start by selecting the cells you want the check or tick to be in. then change the font to Wingdings2 this font does not show letters and numbers but pictures instead. By typing a capital P in a cell formated with Wingdings2 you will see a check mark, rather then a P.
Wingdings is another font that has pictures instead and l m n will give happy , sad and neutral face. Try other letters and numbers to get other characters.