If you want add dynamic date or yesterday date in email body using ssrs tool SQL Server 2017, please fellow these steps:
Step 1>
Upload rdl file .
Step 2> Right click on file
Then click manage
Step 3> In Left menu click Subscription
Step 4> Click New Subscription
You will see this window
Then choose data-driven subscription
Then click edit dataset
Then you will get below window
From this select custom source you will get below window
after filling all type query like you want yesterday date then type below query:
Then click Validate Query AND APPLY
IN SUBJECT TAKE VALUE FROM DATABASE AND SEND MAIL