How to access Apple ID accounts by my wife when I die?

She contact Apple. They need to see a copy of the death certificate and a copy of the will or a document that shows you inherited it.

How to request access to a deceased family member's Apple accounts - Apple Support.    

Either take the device, the above paperwork, and a photo ID to the nearest Apple Store (if it has reopened)

Genius Bar Reservation and Apple Support Options - Apple.    

or contact Apple ID Support. 

 Apple ID - Official Apple Support.    

Contact Apple for help with Apple ID account security - Apple Support.  (Link doesn’t always load)   

Get Support      Work through the screens to get a chat option. 

Apple Support schedule phone call

https://twitter.com/AppleSupport       People have posted it may take an hour or more to get a response.

They have access to your Apple ID account and password, With a court order, as explained in the link I posted, they will provide that information.

You are welcome.