Yes. Deleted text messages can be recovered from an iPhone. This is due to the way that iOS handles the deletion. It does not physically remove the file but only marks its storage as available to the system. This allows the message to be recovered until the time it is overwritten.
Yes. Deleted texts are stored on your iPhone. The deleted text messages may remain on your device for a considerable amount of time if they are not overwritten by the system. To fully and permanently delete all of the text messages you should consider performing a reset on your iPhone.
You can control how long messages remain active on your iPhone, though we have seen that deleted messages can still reside on the device. In your iPhone’s Settings, navigate to Messages > Message History and choose between keeping them for 30 days, one year or forever. The default is forever.