I’m Melissa, a Shopify Guru. Thanks for reaching out. That can be a regular request in relation to wholesale so it is great you have such great interest from customers!
There are a few apps available that can help out implement this on your store. Check them out and see what you think:
These apps allow you to create a catalogue in a PDF format to send out and forward to your customers. Hope this information helps! You can reach out to the Guru team https://help.shopify.com/questions if you have any questions.
Have a great day!
Melissa | Shopify Guru