In the US, trademark use is essential to register your trademark and to maintain it. Without use, there will be no registration and without a use after registration, your trademark may not be maintained.
Using for goods (products) is actually selling your products with your trademark being displayed either on the actual products or their packaging during the sale.
Using for services in the US is actually advertising and performing the services in the US in more than one state or in the US and a foreign country.
Use must be “bona fide” – real sales to real customers. “Token use” is not acceptable.
Use must be in the ordinary course of trade – that means that goods and services must be used in a way which is typical in a particular industry.
Note: the US law says you need to use the trademark in interstate commerce. That means that when you sell your products they need to be sold and shipped to another state or to a foreign country.
To open in a new tab, click: What is use in commerce (in the US)?