Getting Twitter APIs for a client

Hi

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 https://apps.twitter.com/ 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!

thanks
mariette