You can improve your text sign-up process in a few ways.
Use more than one tool. If you’re using sign-up forms, but not using QR codes or Keywords, you may be leaving opportunities unaddressed.
Think outside your site. Add QR codes to receipts and in-store signage, and use the shareable sign-up form in your email communications.
Make sure your sign-up forms are easy to see on your site. Stay above the fold and don’t let the form get lost in your design.
Ask for less information. The more information you ask for in your sign-up forms can often lead to less signups. Keeping the contact fields you require to a minimum to keep your conversion rate higher.