After whatsapp none cares about text messages You will find there are lot of promotinal sms and messages and you dont want this to store in your SIM card so to avoid this you need to follow some tips for samsung s7
Go to setting of Samsung Galaxy S7.
Scroll down to “Applications”. Tap the entry, and then select “Messages”.
Again from settings –> text messages –> Manage messages on SIM card
You will find all text messages which are stored on your SIM card and you can now edit them. You have the option to read, delete or copy the message into the phone memory.
Hope this will help you