Certainly. Open the Tools menu, and Launch Editor.
Open the File menu and click New Data File, and click the Race tab.
If what you're creating is similar to an existing race, you may want to choose New(Copy), otherwise choose New(Blank).
You need to give it a name, and a unique ID. Everything created in the Editor has a specific prefix associated with it that is pre-populated in the unique ID field with a question mark appended to the end. Remove the question mark, and you have 10 total characters to work with. Remember, don't alter the prefix. Some of the background mechanics utilize these prefixes, and changing them can have unintended side effects.
Fill in the description and the summary. For the summary, it shouldn't be longer than one line. If text is entered in excess of one line there's a danger of the text being truncated.
Click the Source button, and choose which Sources the new Race should be visible for. If it's custom to a specific campaign, you can create a new Source specifically for that campaign.
Click Save, then click Test Now. It will go through a file save dialog to create a .user file with your race definition. It should respond with "You may now use <whatever> in Hero Lab". Close the Editor, and the Race should now be visible in the Race window. There's some other, fancier stuff that can be done, but that's the basics.