DKIM not signed and Opendkim not installed

aaPanel over Debian 10

MailServer set up OK

Mail-Tester gives error: DKIM not signed

Service Status trying to find Opendkim

Opendkim not found

And from SSH console Opendkim service is not found

Can I install Opendkim from aaPanel?
If not, can I install Opendkim directly from SSH console?
Or it may cause problems with Mailserver?

Thank you

Fixed

Now I get 10/10 on Mail-Tester, including DKIM signed