Use a tool like Sideloadly to sign the app using your Apple ID.
If you have a legitimate reason to install a Netflix IPA (for example, a customized version for business use), ensure you follow these steps to minimize risks: netflix ipa
Android users have a slightly different experience (they can install modified APKs with relative ease). But iOS is a walled garden. The entire architecture of iOS is designed to prevent exactly what you are trying to do. Use a tool like Sideloadly to sign the