Email validation

Key things to look for are @ symbol, then a dot, then a 3 letter extension for a url, such as com, edu, gov, biz, net, co.uk, however many you want to define.

right(local!possibleEmail, 4) returns the last four characters.  That should be in a whitelist containing .com, .gov, .edu, etc.

Then you can find() or search() for @.

There should be other rules to include, such as no spaces.  So you can exact(local!possibleEmail, cleanwith(local!possibleEmail, " ")

Hi, you can refer this post as well https://community.appian.com/discussions/f/administration/7353/way-to-validate-email-addresses. Mike has shared post regarding and it works well.

Why wouldn't you want to use RegEx?  The (very very) old thread Vikash already linked for you will contain my (very very) old-but-still-working OOB expression rule that handles basic email address validation, however the Regex solution is quite a bit more powerful.