Prefer to start online?
The main office site at getirshelp.com has a full intake form, client resources, and more about the practice. Texas clients are handled the same way as everyone else: directly, by the attorney.
What to have ready
Nothing is required for the first call, but if you have IRS notices, grab the most recent ones. The notice number in the corner (CP504, LT11, Letter 1058, and so on) tells me exactly where you are in the collection process, and that determines what has to happen first and how fast.
If you have not opened the envelopes, that is fine too. You would not believe how many clients bring in a rubber-banded stack of unopened IRS mail. We open them together, and the situation is almost always more fixable than the stack suggests.