Zipcodes in Upload File

Sort the column with zipcodes and select only the cells that include zip codes with 9 digits without a dash between the zip and remaining 4 numbers. (Tip: do not select the ones that are 5 digit zipcodes)

On the Home tab, next to Number in the Number Format box  , click the arrow, and then click More Number Formats.                                      

In the Format Cells dialog box, under Category, click Special.

In the Type box, select Zip Code + 4