If you want to make requests client-side then you have to use the Implicit auth flow https://dev.twitch.tv/docs/authentication/getting-tokens-oauth#oauth-implicit-code-flow, and have your users log in to your site. They only need to connect to your app once, after that the auth process can be transparent to the user unless they disconnect from your app. Even if you don’t need any user data, you still need an OAuth token to make requests and if you want to do it client-side then the implicit auth flow required.
If you want to make requests from your Server, then you can just use the Client Credentials flow https://dev.twitch.tv/docs/authentication/getting-tokens-oauth#oauth-client-credentials-flow to get an App Access Token, which doesn’t require any user intervention to obtain, and make requests with that.