If you have a corporation or limited liability company outside of Texas that is doing business in Texas, the law requires you to have a registered agent in the state to accept service of lawsuits.

A registered agend is required for each entity, that is, each corporation and LLC

Failing to register and designate a registered agent may foreclose or hinder the company's ability to legally enter into contracts and gain access to the Texas state courts. Moreover, it may subject the company to monetary, civil, and possibly criminal sanctions.

While there are many companies that can act as a registered agent, you may want to use a lawyer in Texas for your registered agent.  Why?  Because a lawyer can do more.  The time you'll really care who your registered agent is will be when you are on the defensive side of a lawsuit.  Then you'll have to find a lawyer to defend you and give him or her a copy of the suit before the deadline to respond expires.  You'll be under the gun.

Instead, you may want to consider using an attorney.  Make sure the attorney has litigation experience and review the contract outlining what is and what is not covered in the registered agent agreement.

Good luck,

Andrew