Question : How to create List box in Excel. User can select one or more entries

I need to create a report based on selection from 3 different list boxes.  How to create list box and then pass those parameters to the SQL code to generate a report.

Answer : How to create List box in Excel. User can select one or more entries

I would use Data Validation on 3 cells, setting the 'Allow' option to List, and either typing in a comma separated list of values, or using ranges on a worksheet. You can then just refer to the three ranges when building the SQL.
Alternatively, you can add listboxes fro the Control Toolbox, set their ListFillRange properties to worksheet ranges and the LinkedCell properties to the putput ranges, then refer to those cells as the parameters.
Regards,
Rory