When your company expects to transact business outside your state of formation, your company may be required to qualify as a "foreign LLC". There are many "company formation companies" that can file the necessary paperwork to qualify your business as a foreign corporation in any of the 50 states.
A LLC is considered to be domestic only in the state where it was formed. In all other states, your company is regarded as a foreign LLC. To qualify your company to transact business in another state, you must register for a Certificate of Authority to transact business in that state. The consequences of not qualifying in a foreign state in which your company transacts business may include loss of access to that state's courts and potential fines.
Additionally, LLCs are subject to taxes and annual report fees in both the state of formation and any states where the LLC is qualified as a foreign LLC. Additionally, most states require LLCs to have a Registered Agents within each state where the company is qualified. This agent must be available to receive important communications from the state and others on behalf of the company.