Create an instance of the OpenAI service with trial account

Question

I need to create a project that receives some audio files and qualifies a series of variables depending on the conversation held between the agent and the client of each of these files. For this, my idea is to use speech to text for the transcription of the audios and OpenAI for the qualification of the call in an Excel. I have created a trial to test this idea and understand the Azure services I need, (I do not know if I would need any more of the above mentioned) The problem is that it is not letting me create an instance of the OpenAI service, in the creation process, it does not let me choose from the list of prices, as it does not provide me with any option. Could someone help me with this? Thanks a lot! Pablo