=IF(left(T1,10)="ID: msanta","Manuel",IF(left(T1,10)="ID: mbrown","Melissa",IF(left(T1,10)="ID: adarli","Annette",IF(left(T1,10)="ID: mrivas","Melody",IF(left(T1,10)="ID: wgorma","Wynema, IF(left(T1,11)=B6: jponsar","PA",IF(left(T1,12)="ID: lkrieger","PA",IF(left(T1,11)="ID: ltruong","PA",IF(left(T1,10)="ID: pboyer","PA",IF(left(T1,11)="ID: fberaki","PA", IF(LEFT(T1,9)="ID: pbelt","PA", IF(LEFT(T1,11)="ID: plee013","PA",IF(left(T1,3)="ID:","WIP by Others")))))))))))))"

Change the cell formatting from Text to General. You may need to repaste the formula in afterwords. – Brian Jun 11 at 23:20

The formula, in general, is not correct (several incorrect spaces or missing parentheses). First, fix the formula and then try it. – Yisroel Tech Jun 12 at 2:19

You don't specify what application you're using, there is no information on what the cell references refer to or what the data looks like (assuming this is some spreadsheet), and no explanation. Just a ridiculously long formula. – fixer1234 Jun 12 at 3:37
Try removing formatting from the cell, and then readding the formula. Also, I'm pretty sure that it just shows the formula if Excel (I assume) encounters an error.
You have several errors in the formula itself, all together might certainly cause Excel (at least when you Paste it into the cell without Editing the cell) to not recognize it as a formula at all.
I think that the correct formula is supposed to be:
=IF(left(T1,10)="ID: msanta","Manuel",IF(left(T1,10)="ID: mbrown","Melissa",IF(left(T1,10)="ID: adarli","Annette",IF(left(T1,10)="ID: mrivas","Melody",IF(left(T1,10)="ID: wgorma","Wynema",IF(left(T1,11)="ID: jponsar","PA",IF(left(T1,12)="ID: lkrieger","PA",IF(left(T1,11)="ID: ltruong","PA",IF(left(T1,10)="ID: pboyer","PA",IF(left(T1,11)="ID: fberaki","PA", IF(LEFT(T1,9)="ID: pbelt","PA", IF(LEFT(T1,11)="ID: plee013","PA",IF(left(T1,3)="ID:","WIP by Others")))))))))))))
You can try this one.
(The errors in the formula include: Quotation mark at the end of all parentheses, B6: jponsar" instead of "ID: jponsar","Wynema missing quotation mark.)