You have opened a project and either opened or created a symbol in the symbol editor (Utilities > Master data > Symbol > ...). Edit > Property arrangements.
In this dialog, you create and delete property arrangements. These can then be selected and edited in the Property placement dialog, in the Property arrangement drop-down list.
Overview of the main dialog elements:
The popup menu provides - depending on the field type (date, integer, multilingual, etc.) - the following menu items: