How to use Ctrl + D in Excel
To do this, Excel provides a hotkey. It is used to make a duplicate data cell value. Following is the step to make duplicate or overwrite.

Excel is a data oriented software produced by Microsoft. It is a data modeling application. Excel enables users to organize and manage data in spreadsheets. In most cases, we face a situation in which we have to overwrite the one cell’s values to the entire column or in a specific range of cells in a column.
Step 1 – Select the data cell

To do it yourself, above is an animation as an example.
– Select a cell where you wish to overwrite or duplicate. In this case the selected cell is A4.
– Drag with the handle till you want to make a duplicate.
– Press CTRL + D.
– By pressing the enter key, results will be given.
Resultanly, by pressing the hot key ctrl + d it overwritten the column A value and made duplicate in column B.