We would suggest to share the customer ledger link, so that all the transactions will be shown in the ledger and upon clicking on the invoice number the invoice details will be shown and can download the invoice. Please check the below mentioned steps:
Step 1 : Please go to Customer section >> Click on Ledger.
Step 2 : Click on Share button >> Share on WhatsApp / Copy the link and share.
Step 3 : When the customer opens the link, they can see all the transaction details.
Step 4 : Upon clicking on the invoice number, the customer can check the invoice details and download the Invoice as well.