Hello @subhajit ghosh 

To read the data from the Text file which is (Binary data type), Now once we import the file, Importing I suppose you are importing from the local system. It can be uploaded from the upload widget, So now we have a file now we need to read the data which is in our text file o achieve this we will use a system extension called BinaryData which has a method BinaryDataToText. After you get the text, you can split it by lines, by using the Text extension's method String_Split.

You can add the dependency of these  

Now once we have the data we can assign the data to a variable and then bind that variable to the text input on a screen.
Now if we want to achieve copy paste thing, We can do it directly with a button click or on an action 
Where we will call the entity Create action, Here you need to create a database with an attribute(name), Now make sure that the data type text has enough length to store the data.
Once the data is stored in a database. Would you like to export it via excel ?

If yes then you can directly use RecordList to excel widget available on server action, you can use that it will generate a binary file which you can pass on the client side on the client action on the download node.

Hope this helps
Best Regards
Tousif Khan