How do I keep leading zeros in my CSV file, like 00001?

Spreadsheet programs like Excel drop leading zeros because they treat the cells as numbers. To keep them:

1. Select the cells for your numbers.
2. Right-click (Control-click on a Mac) and choose Format Cells, then Text.
3. Now type or fill your numbers. You should see the zeros, for example 00001.
4. Save as CSV.

If you reopen the CSV in Excel later, the zeros may look like they're gone. They aren't. Excel hides them when it opens the file. As long as you saw the zeros when you saved, your file is fine to upload.