Hi Bhargavi
The datasource for the PRPT will be an SQL query . You can use the ${env.username} variable to get the logged in user Perhaps like this...
select
si.sensitive_name,
si.sensitive_date
from
sensitive_information as si
where
si.allowed_user = '${env::username}'
The value of ${env::username} will be replaced with the logged in user.
Here's a tip on how to set it when you're developing a PRPT on your desktop
https://www.bizcubed.com.au/set-envusername-for-testing-prpt-in-pentaho-report-designer-prd/