Logging a spec send is beneficial for when users send out spec send directly from Outlook - as currently there is no way to track them back from Outlook to Mercury.
To log spec sends (for both Candidates and Clients), select Spec Sends from the side menu > +New.
Fill in the relevant fields. The Name field is required.
To view all Spec Sends for a Contact (Candidate or Client) go to a Contact record > Related > Spec Sends