How do configure Copy down functionality on the Line item Grid?

Summary

We want to copy down the value from current cursor column to following rows on the line item grid

Content

Hello,

I am looking for help in designing the Copy down functionality on the line item grid. There are 10 rows on the line item grid. I have put the cursor in the first row and enter the $100 in the list price column. Now if I click a button copy down,  the system should populate $100 in the list price column of all the following rows (remaining 9 rows) on the line item grid.

Any help in achieving this functionality is appreciated.