I can't seem to find her and I've done the mission between her and legion but after that she is not in the war room so where is she now I've looked everywhere or dose she not appear on the Normandy she is on my squad. Answers much appreciated.
After the battle for Rannoch and her surviving the outcome, Tali becomes the Quarian ambassador on the Citadel. She will eventually rejoin you later on. If you have a romance with her, she will join you in your quarters.
Edit: Check your messages in your quarters or next to the star map.
After Priority: Rannoch, you will receive a message from Tali, which you can read in your quarters or at the terminal by the Galaxy Map in the CIC (Combat Information Center). She'll be waiting for you in Engineering, right in front of the drive core (where Adams, Gabby, and Ken are). If you made peace between the geth and quarians, prepare for a surprisingly happy conversation.