Hello,

1. Sorry, I did not understand where do you want to add the download button.

2. Make sure that you have enabled the “Share buttons” option for the product page in Theme Settings > Single product > Elements: https://prnt.sc/KBCFPkeFi3kL

Go to Theme Settings > Social profiles > Share buttons and enable networks you want to display.

Please note that Instagram don’t have such functionality for “Share” like on Facebook or Whatsapp, therefore we cannot influent it, unfortunately.

Regards,