There are several options available when exporting:
Output Sample Rate
Select the sample rate you would like to use as a default value when exporting. Some formats may have their own settings and can override default sample rate if set.
Output Channels
Select the channels you would like to use as a default value when exporting. Some formats may have their own settings and can override default channels if set. Use Surround Sound button to configure surround sound settings.
Audio TagClick this button if you would like MixPad to add meta-data tags to your exported file so that music libraries can display information about your track such as Artist and Album. You can edit the project meta-data from Menu->File->Project Options.. or Menu->Edit-> Edit Audio Tags...
Export selected work region onlySelecting this option will only export the region of your project inside the working region you have selected. To select a working region you can set the start and end points of the region in the main project timeline. You will only see this option if there is a selection in the project timeline.