If you want to apply for a trademark or already have one, you need to use a special website called the Trademark Electronic Application System (TEAS) at https://teas.uspto.gov to send in your documents and information. You’ll also need to give the USPTO (United States Patent and Trademark Office) an email address to send you messages. There are a few exceptions to this rule, like if you’re applying for a trademark from another country or if you’re using a special kind of trademark that’s related to scent, flavor, or something similar.
If you try to send in your trademark stuff on paper instead of using the TEAS website, the USPTO might not accept it and will throw it away. They might also send back any checks or money orders that you included with your paper submission.
If you have to deal with the Trademark Trial and Appeal Board (a group that helps with trademark problems), you’ll need to use a different website called the Electronic System for Trademark Trials and Appeals (ESTTA) at https://estta.uspto.gov/. This is where you’ll send requests, oppositions, cancellation requests, appeals, and other documents.