Hard time to record for a voice over and it doesnt go above 15hz

Difficult to answer this, because it sounds as though you've been dropped right in it...

These will be kHz you are talking about, not Hz - there's a very big difference. The problems with your client request are that firstly it's possibly unreasonable, and secondly it may have expressed correctly, but you didn't understand it. Or worst of all, both.

The human voice does not contain any useful information above 12-13kHz, but this may not have been what they are talking about - it's hard to tell. If you set up a recording so that it's mono, and at 48k sample rate then the system is capable of recording up to 24kHz, but there's no way your microphone could produce output at that frequency; you would just record the normal output of a human voice, which has a range that doesn't extend anywhere near that far.

Audition always records in Wav format - that's its native standard.

Hello,  I am super super new with this software. I have some issues and I can't record above 15hz and my client ask me to be 20hz and above. Also audition doesnt let me record or I have a hard time to record. All the files I upload are set up at 15hz.  It is set up at 48000, mono like my clients requested. What are the extra setting should I do to make it work ? My mic is a TONOR Micro PC, USB (low price and its quality too I guess)

[Mod note: I've kept both of your posts in a single thread, because having them in two threads makes any answers you may recieve potentially rather confusing if they are spread across two.]