This is the Greek word Tetestai
In English it translates to “it is finished.” In the New Testament, it was said to be used on receipts in business meaning “debt paid in full.” In a judicial context for court, it means “fully served.” In military context, Tetelestai means “battle won.” A word used for triumph and victory.
So when Jesus died on the cross and cries out Tetestai. He is saying the perfect sacrifice is finished the debt has been paid in full and the spiritual battle for the keys of the gates of hell has been won.
All we have to do I believe in him and he will freely give us all of the heavenly gifts