In Communications> Email where your email is already created:

  1. Click Receiver Query
  2. Expand Address Types
  3. Expand the desired Address Type
  4. Highlight Zip/Postal Code
  5. Click Add
  6. Select the second radio button to search by zip code radius
  7. Enter the radius settings
  8. Click OK
  9. Click Save and name the Receiver Query
  10. Click Done