Using Webview/desktop:
Log in and view your Muso Profile
Go to 'Edit Profile'
Toggle Y next to the question "Do you have an ABN"
Enter your Business Name
Type in your ABN
Confirm if you're registered for GST
Save changes
Muso mobile app:
Log in and view your artist profile. Scroll down to view 'About' then tap 'Edit'.
Tap to select Yes that you have an ABN and enter your Business name and ABN (both are mandatory fields)
(optional) Flag that your ABN is registered for GST
Save (top left corner) all changes before exiting
*note: if you have more than one profile linked to your Muso account, you can add a different ABN to each one if needed