I saw it in the note titled HUMAN TRAFFICKING IN PHYSICAL AND HEALTH EDUCATION JSS2
The difference between “labor” and “labour” lies primarily in their spelling conventions, which are associated with different regional variations of English.
“Labor” is the preferred spelling in American English, while “labour” is the preferred spelling in British English and other variants, such as Canadian English and Australian English. These differences in spelling are known as American and British spelling variations.
Apart from the spelling distinction, there is no inherent difference in meaning or usage between “labor” and “labour.” They both refer to the same concept, which is the physical or mental effort exerted by individuals to accomplish tasks or produce goods and services.
For example, “labor/labour unions” refers to organizations that represent and advocate for the rights and interests of workers, and “labor/labour laws” are regulations that govern employment and working conditions.
In summary, the difference between “labor” and “labour” is simply a matter of spelling based on regional conventions in English-speaking countries.