Tell me a good way to respond to customer requests. That is, what things should we put in it? Is it okay to send a portfolio that we have?
Check out: Fiverr Help and Education Center (Responding to Buyer Requests).
The good way to respond to customer requests:
First, read carefully what the client needs
Tell him what you will do for his project, how you will do it
Use very polite language and simple English
Tell him the benefits he will get from you
Ensure him that you are the expert in your niche
Give some extra work which will make your client happy
Thank you so much for your very valuable advice
Portfolio is the most important thing for every freelancer.