package.json is a manifest file for Node.js projects, which includes things like metadata (the project's name, author, etc.) and a list of dependencies (other packages that the project depends on). It is usually located at the root of a project, and you can tell which package manager is being used by the accompanying 'lock' file. For example,
package-lock.json is used by npm,
yarn.lock is used by Yarn, and
pnpm-lock.yaml is used by pnpm. Check the
package.json file for
scripts to see what commands are available to run, example:
npm run dev.