AN ARTIST CAN NOT BE BOTH PRIMARY AND FEATURED ON THE SAME TRACK
Do not list featuring artists as a primary artist in the release level. Only list them on the track level. Do no type (feat. XXXXX) in the title field.
Use the drop down menu for Featuring artist to add them and it will automatically put that information in the title. This helps with consistency and will send properly to the stores.
If it is a single you can list the featured artist on the release title.
Release Title: “Drop the Treble (feat. Pretty Singer)”