AirDrop in WhatsApp:
How can I access AirDrop within Whatsapp to transfer a link from within a message from my iPhone7 to my iPad6?
You would need to open the link first in a browser or app, and then use the share option from there to Airdrop it.
WhatsApp does not let you Airdrop links directly.
Alternatively if you have Handoff and continuity enabled between your devices, you can use the universal clipboard optonto copy the link on the iPhone, and have it be available to paste on the iPad.
See here: link-> Use Universal Clipboard to copy and paste between your Apple devices - Apple Support