Hi @soundarya.a ,
have you tried using “Join datatable” activity ?
Here is Link (if in case you want to learn more about it ) : https://docs.uipath.com/activities/docs/join-data-tables
For your scenario, you can use LEFT JOIN as shown below
DT 1 : Once you perform Read range of Sheet1, call the datatable as “DT1”
DT2 : Once you perform Read range of Sheet2, call the datatable as “DT2”
DT3: output data
Hope this help!