Binance.us and Binance.com are different services. Binance.us is the cryptocurrency exchange service for USA citizens. If you are an American citizen in the United States Binance.com will not allow you to sign up there, you would have to go to Binance.us
This cryptocurrency exchange service is quite possibly the slowest, buggiest and confusing of all the cryptocurrency exchanges. As confisuing as it may be the exchange does offer good crypto coin options and one of the main sources for buying Dogecoin in the USA.
The android app for this service has a terrible rating on the Google Play store and I can see why. Signing up took me several tries, adding money to my account was buggy and buying crytpocurrency had network issues and actually caused me to buy two rounds of cryptocurrency.
I would not recommend this service but if you are looking for a safe service Binance.us seems to be a legit company based in the United States.