Its happened also to you to receive an important message asking for something to remember and, at the end of the day, completely forgetting about?
"Remember" its made for this. Its a simple text reminder compatible with Apple Watch with the unique feature of been able to store text to remember via the Share controls from every application.
What it is this "unique feature"? It remove one critical step from the moment when you receive a WhatsApp Message and the Reminder itself. You dont need to copy the text, open the App and paste into (one of the main reasons why Reminders are not so popular in some basics and rapid stuff).
Just share the message with Remember and the application will process the text.
Nothing more easy.