How to copy data in excel format and paste in multi line text box with formatting in selenium

I need a help on the below scenario.

Scenario: I need to copy the range of data (E.g.- C3:E3) from excel and paste it in multi line text box. Here I cannot add the data in a list and paste it in multiline textbox since this multiline textbox will only allow the excel formatted range data.

To be more precise, There is a form which has multi line text box, button and a grid. When you paste the data( i.e range of data from excel) into the multi line text box and click on the button then the data will be displayed in the grid. Here, if you manually enter any data in multi line text box and click on the button then the data will not be imported in the grid, since we have not pasted the data from the excel.

Please let me know how can I achieve the above scenario using selenium c#