Quite a broad topic for an essay. I would say, you might want to make it more precise. Of course, you can leave it that way and write about labor force in general, cover the definition and give a broad explanation of what is it, where used and how.
You can use a broad explanation like this one.
The workforce or labor force is the labor pool in employment. It is generally used to describe those working for a single company or industry, but can also apply to a geographic region like a city, state, or country. Within a company, its value can be labeled as its "Workforce in Place." The workforce of a country includes both the employed and the unemployed. (And so on)
Still, if you want to make your essay interesting and original, you would need to consider this topic in a more specific and narrow manner.
I can offer you to look through some examples written by other students on the topic of the labor force, so you get the better idea of what I mean by ‘making a topic more specific.'
Another way to consider this topic would be writing about the labor force in a specific country, state or city. This will allow you to make your research more throughout. You may look through this particular paper to get a clue how to write an essay like that.
Also, you can include an additional aspect of analyzing, thus getting a topic about a specific country+ an issue, and avoiding general statements and wordiness in your essay. Like it is done in this example:
Hope it helps.