@saumyaupadhyay, when looking at your xslform and your csv file I could see the following:
Your CSV file:
Issue number 1:
If you look at your xlsform (where I have marked 1 of
key, they do not match the header name you have specified with your csv file which has
Key. So, here you will have to make them either
Key or provide a different name in both the places.
Issue number 2:
Line 6 of your xlsform has a
select_multiple question type. You have tried to use a pulldata function for the same which is not supported. If you wish to use a select_multiple from a csv file you will need to use other approaches such as
select_multiple_from_file as outlined in this support article Select One or Many From External File Question Type.
To learn more on pulldata, feel free to go through our support article Pull Data Functionality in KoBoToolbox.