Hi @Uraiba_Khatri,
Great - a Business subscription means you can create custom rules in Asana, which means you can build an Asana rule with the Flowsana action.
Create a custom rule. Set your trigger as “Task moved to section [Approved]”. Scroll down to the bottom of the Actions list and select “Send an email notification” in the “Flowsana” area:
For the fields in the action, set “Send the notification to” to “an email address in a custom field”, then select the name of the custom field containing the applicant’s email address (in my example it’s called “Assign To”):
For the Subject and Body fields, enter whatever text you’d like to go there! Note that for both the email Subject and Body, you can include lots of different values from the task itself using Flowsana’s Variable Substitution feature, which you can learn about here.