I am trying to clear my current Mac to send it back but the erase key is unclickable

This article should assist you with getting your Mac ready to return

https://support.apple.com/en-us/HT201065

xana13 wrote:

I need to send my Mac back soon and need to be able to clear it and set it back to factory settings

Returns & Refunds Order status

https://www.apple.com/shop/help/returns_refund