post https://api-wallet-sandbox.venly.io/api/users//signing-methods
This endpoint allows you to create a signing method for a user, whether it's their first or an additional one. The first signing method must always be a six-digit PIN, and does not require the Signing-Method to be passed in the header. For creating subsequent signing methods like BIOMETRIC/EMERGENCY_CODE/PASSWORD, include an existing valid Signing-Method in the request header.