yes other option is to use PayPal from another country but I need some paper to open business account or registered company. seems PayPal in us won't accept only EIN for registrationIt's unfortunately not quite that simple. You might want to start here and familiarize yourself with ECI: Effectively Connected Income (ECI) | Internal Revenue Service There are more articles and resources available that explain ECI a in even more depth.
Furthermore, an LLC is normally considered a pass-through entity which itself is not taxed. That means the profits of the LLC become your personal income, which further muddles the waters with regards to ECI.
Enforcement of ECI for small businesses is lax or non-existent. It's not on the IRS' radar to pick up on a few thousand bucks sold to US customers through a foreign-owned LLC. But unless US customers are going to be a significant revenue source, you can do what many businesses do and simply not allow US customers.