Subject line: Received your inquiry for <short name of their inquiry>
Just got your inquiry for <app/software name they mentioned> on Axonator.com
I would like to understand your challenges and high-level requirements. Do you have sample forms? If yes, can you share them with us?
It will help me to understand your app requirements.
Can you please confirm your availability for the call? We will discuss your challenges and evaluate how Axonator can help you with <app name>
Let me know your availability so I can send the meeting invite.