Set Reminders & Timers
If there’s something you know you won’t remember to do, have Alexa remind you to get it done. Say, Alexa, “Remind me...” and the name of the task. She will ask you to set a time and confirm the reminder.
Only the speaker that hears the command will repeat the name of the task when it's time, but your smartphone will also get an alert. Unfortunately, you can't set a reminder on more than one Echo with a single command.