Add a Default Signature to all SMS Outgoing Text Messages Merged

I use the SMS texting all day long with my clients. I'm an Insurance Agent. I'd like to have the ability to create a Default Signature that will be sent will all my outgoing SMS text messages that I send to my clients. Having a Default Signature setting will be very helpful and time efficient when texting my clients. Without it I spend a lot of time typing a Signature at the end of each text I send out. This would not only by time efficient but also makes the text more Professional.