@Balaji Ravikumar Thanks for reaching out to Microsoft Q&A, apologize for any inconvenience caused on this.
Could you please confirm whether you are using Azure SingalR Service or SignalR service. If you are looking for Azure SignalR service, you look at this documentation steps to Broadcast real-time message from a console using RestAPI.
If you are talking about the SignalR service do let us know that so that re-tag this thread so that right SME folks will be engaged accordingly.