What is the difference between, and the correct usage of, the words "toward" and "towards"?

They are completely interchangeable and have both been used since they first appeared in English in the 9th century. In North America, people are more likely to use toward, while everywhere else towards is more common. Both forms, however, are used everywhere and both are completely correct. There have been some suggestions about different usages (e.g., one is the adjective, one the adverb or preposition), but they are not widely accepted, and are at variance with the fact that both forms have always been used interchangeably.

https://www.merriam-webster.com/grammar/toward-towards-usage

(It's a bit like grey vs gray.)