The Samsung Galaxy phone has two text messaging apps, Samsung Messages and Google Messages.

The steps for sending a scheduled text vary slightly between them.

i. Samsung Messages (the app icon with three dots arranged horizontally)

1. Tap + next to the text input area > Schedule message and set a day and time.
   

ii. Google Messages (the app icon with three horizontal lines)

1. Tap + next to the text input area > Schedule send and set a day and time.
   

When you have finished typing the message, you can go ahead to tap the Send button. A little clock will appear next to the message to show that it's a scheduled message that will send out according to the set time and date.