I have ModellHub .com (ModelHub .com SOLD for 6,500 USD in 2011)
Whether you’re modelling or modeling, you’re doing the same thing. The only difference is in the spelling—the one with the single L is preferred in the United States, while the one with two Ls is preferred everywhere else, it’s one of those “United States vs. The Rest of the English-Speaking World” things.
There are plenty of small, interesting (or sometimes annoying) ways the two major variants of the English language—British English and American English—are different. The double L we see in modelling is one of them. This is the preferred spelling in all English-speaking countries apart from the United States.
Source:
https://www.grammarly.com/blog/modeling-or-modelling/