After an offer has been accepted by the seller, the buyer must arrange for the property to be inspected within a set time period. The days allowed would have been included in the contract of sale but should be done as soon as possible in case it is necessary to obtain bids from contractors for any repairs.
The three main areas of inspection are structural, mechanical and pest evaluation. The promulgated form used by inspectors sets out the items reviewed during an inspection. A TREC sample inspection report form can be found here: Inspection report. It is important to choose an inspector who is not only licensed but sufficiently experienced in the integral aspects of a home. The Houston Association of Realtors provides a partial list of home inspection companies which you can find here: Houston Home Inspection Companies.
For further information on inspections you can download a list of questions and answers from TREC here: Questions and Answers, Additional Questions and Answers.