As you may be finding out Google used to have the capability to send yourself text or SMS reminders prior to your Events. This feature went away January 2019.They still allow email reminders to be send to yourself, and replaced the SMS Reminders with Mobile in app Notifications.Now Google Calendar never had the ability to send clients or customers SMS reminders. This is where systems like GReminders fill the gap.If you run a services company and you charge for your time, its clearly a total waste of time if your client or customer doesn’t show. You lose money while another customer waits. This is what you want to use Reminder systems for. https://www.greminders.com/how-it-works