I need to create a form with 2 columns (A & B), and when user select a value from the dropdown list in column A, all the values in column B that are related to Column A selection will show.

Column A -> Dropdown list with 5 values (vendor1,vendor2,vendor3,vendor4,vendor5)
Column B-> By default will not show anything, once user select a vendor (eg. vendor1), all vendor1's products will show.

Can someone please kindly advice? Thanks.