You can get a toll-free number from the Plivo console (Phone Numbers > Buy Numbers) or through the Plivo Toll-free Verification API.
All of our toll-free numbers are voice-enabled by default. To add SMS functionality to a toll-free number, please complete the toll-free verification process. Raise a verification request via the Plivo Console or through Plivo's Verification API. The carriers will validate your use case, and if approved, you can start sending messages using the verified toll-free number.
You can read more about toll-free best practices and guidelines in our documentation.