DAX code
Aging Bucket =
VAR DaysOverdue = DATEDIFF('Invoices'[DueDate], TODAY(), DAY)
RETURN
SWITCH(
TRUE(),
DaysOverdue <= 0, "Not Due",
DaysOverdue <= 30, "0-30",
DaysOverdue <= 60, "31-60",
DaysOverdue <= 90, "61-90",
"90+"
)