Hi,
In the Features tab of the configuration (or in the hikashop filter module options screen if you're using that module to display the filters), you'll find an option to define the number of columns of the filters area.
Then, in each filter, the "number of columns" option allows you to set the number of columns that the filter will use.
So you want to set the option of the configuration to 3 and the number of columns option of each filter to 1 if you want your filters to be displayed on three columns.
It's also possible to override it with CSS (you can use !important to override the CSS width of the div with your own width).