Getting Twitter APIs for a client


I have never been certain if it is OK for me to create a Twitter app for a CLIENT's Twitter feed (for consumer key, access token etc) by logging into with MY OWN Twitter login details and then creating an app with my client's organisation and website details?

Or do I need to ask my client for their Twitter login details and create the app as if I were them?

Hope that makes sense.

Look forward to finding out for sure one way or the other!