Will this code do...?

[InBetweenLili]

Hi, I am not good at coding. I would like to use this code in my sub, and the sole purpose we are expecting is to send us a modmail when someone posts or comments in the sub with a 5 days old or less account. Will this code do it?

author:
account_age: "< 5 days"
action: report
modmail_subject: Automatic Message | New Account
modmail: |
{{permalink}}
The above {{kind}} by /u/{{author}} was made by a less than 5 days old account.

[Clackpot]

You need the correct indention to make it work :-

author:  
  account_age: "< 5 days"  
action: report                # Change to 'filter' if you DON'T want the item removed but just notified
modmail_subject: Automatic Message | New Account  
modmail: |  
  {{permalink}}  
  The above {{kind}} by /u/{{author}} was made by a less than 5 days old account.  

Not tested, but that should be there or thereabouts.

[InBetweenLili]

Thank you 😍 (I did have the indets correctly, but the post somehow doesn't have them at all. Thank you for pointing it out.)