WordPress Auto Spinner plugin can rewrite WordPress posts by clicking a button or automatically on publish. It supports many APIs including smodin.io Rewriter/Paraphraser/Text so here are the steps to get your smodin.io API key

1- Visit this link https://rapidapi.com/smodin/api/rewriter-paraphraser-text-changer-multi-language

2- Create an account if you do not have or log in if you already have an account

3- visit the pricing tab and click the subscribe button for the free package or choose another package that suits your needs

4- return to the endpoints page here  https://rapidapi.com/smodin/api/rewriter-paraphraser-text-changer-multi-language and copy your API key