Check your "UNCATEGORIZED" category in your library.
Also the search at the top of your library might reveal that its actually there... somewhere unexpected.

Where did you purchase it was it on Steam store?
What was used to pay for it?
Credit card debit card pay pal?
Your bank should show the transaction details

Are you logged into the right account on Steam?
The Store page should now show You already own the game.
https://store.steampowered.com/app/2807960/Battlefield_6/

Originally posted by Hellen Keller:

i Purchased battlefield 6 and it shows in my bank accout the money has been taken but the game and my purchase history doesnt show it there

Your game badge says you haven't added a new game to your library since September 21. Either the purchase didn't go through or it's still pending.