YouTube Studio is your home base for posting videos and making edits to your channel. To update your channel's basic info like name, profile picture and banner, just log in and tap 'Customisation' to see your options.
You can also make changes to your channel using the Studio Mobile app. You can tap 'Your Channel' and then 'Edit Channel' to update and edit how your channel looks to your viewers. Note that you can only change your channel's name three times every 90 days.
Read more about managing your channel