http://sparrowa7io5pz6ud3ehqzosvepbxbxt2zphmkjsylp2zgxooko23pqd.onion/docs/spending-privately.html
Each wallet can create this identifier deterministically, called a payment code.
It’s similar to an xpub, except that no information about a wallet can be learned from it.
In this sense, it is safe to share. The payment code is however quite long, making it more difficult to share in person.