The lookup multiple rows enrichment returns all columns from the target table by default. If you're not seeing all columns, it might be a display issue in your current table view. [1]
Try clicking the Columns button at the top of your table to check if some columns are hidden. You can toggle columns on/off or click Show all columns to display everything. [2]
The enrichment has an optional Limit parameter that controls the maximum number of rows returned, but this doesn't affect which columns are included - just how many rows you get back.