@Praneeth
may be this will help, please try the below code in Tab birth-day reminder range("E9")
=IF(C9=TODAY(),HYPERLINK("mailto:"&D9&","&G9&"?subject="&C$4&"&body="&SUBSTITUTE(SUBSTITUTE(SUBSTITUTE($C$5,"$",B9),"@",$C$6),CHAR(10),"%0a"),"send e-mail"),"")
say you have another email id...