Answers for "yarn add npx create-react-app"

yarn create react app

// Go into the folder where you wish to create your app
yarn create react-app appname

yarn create react app

npm install --global yarn
yarn create react-app my-app

How to create react app with yarn, npx or npm

npx create-react-app app-name //With npx, the CLI uses npm to install dependencies
npm init react-app app-name // With npm, the CLI also uses npm to install dependencies

yarn create react-app app-name // With yarn, the CLI uses yarn to install dependencies