When LeashTime generates an email without first opening an email composer, the system gets the email's From name from the Short Business Name supplied in ADMIN > Preferences > General Business. If that is not set, it uses the regular Business name in the same section.
In LeashTime email composers, the From name defaults to the full name of the person who is logged in. A manager can override this default in ADMIN > Communication Preferences. At the top of that page is a link called "Your Own Preferences". The manager can change the "From Name in your emails" preference to a more familiar form (e.g., "Kitty" rather than "Catherine") or to the business name or something else entirely.