Sending Invoice and Payment Receipt Link to Customers

Sending Invoice and Payment Receipt Link to Customers

Hi,
I have 2 problems"
1)We wanted to send Zoho Invoice Link on Whatsapp programatically usign API so that the customer clicks the link and downloads the PDF of the invoice along with the Payment Receipt. I am unable to do this.
Which API should I use to generate the link to send invoice link to customer. I was trying to find the API for this.Unable to find it.
2) How can I send the Zoho Invoice Link such that the payment receipt is also added to the same link. for downloading?
Quick help would be highly appreciated

Best Regards,