1. On the Output tab of the Export, expand the Constituent Information section and select the Social Insurance Number (SIN) field
2. Once this field has been selected, single-click to highlight the SIN field in the right window of the Output tab
3. Click the Format button
4. Choose the option for "Masked" or "Not masked", as needed
5. Click OK

*You may also access these options by double-clicking on the SIN field after it has been selected.