We can't

This is a workaround - creating a new sub-customer

There is no option to add a ship to address to a customer, as there was in desktop

Some of our customers have hundreds of ship to addresses

Each one requires a sub-customer - with all the relevant information for an entire customer (tax info, terms, email, etc)

Leaving us with a cluttered mess of 1000s of sub-customers

Users have been asking for this feature for years

All we're given is a clunky workaround over and over