John 19:30 when Jesus had received the sour wine, He said, “It is finished!” bowing His head, He gave up His spirit.
Let us break this verse into parts and meditate on it:-
Received the sour wine
There are many things we learn from this as below:-this 1) To Fulfill Prophecy -> Psalms 69:21 They gave me gall for food; for my thirst they gave me vinegar to drink
2) Jesus received the sour wine the second time only, not the first. The first time he refuses wine since it was adultered with gall or myrhh which would kill the pain
Matthew 27:34 sour wine mingled with gall to drink. But when He had tasted it, He would not drink.
Mark 15:23 wine mingled with myrrh to drink, but He did not take it. ("oinos" which means simply, wine.)
John 19:29 they filled a sponge with sour wine, put it on hyssop, and put it to His mouth.
Gall = bitterness of spirit. Myrrh is narcotic and in embalming (John 19:39). The first time, the wine drugged with bitter narcotics, the effect of which would be to stupefy him, he did not receive. Afterward, some drink free from drugs was given him, which he accepted. ("ozos" which is a mixture of sour wine or vinegar and water.)

It is Finished
This term "It is Finished" is mentioned 3 times in the Bible. Apart from this verse it is also mentioned at the end of the First chapter of First Book (Genesis 2:1) & Start of Last chapter of Last Book (Rev 21:6)
In Genesis 1 after the 6th day of creating man, God is finished. In Rev 21:6 Jesus renews mankind and says Its done. Here Jesus says it is finished in His 6th statement. (Pls don’t connect this to the 666 number :)
Rev 21:6a It is done! I am the Alpha & Omega, the Beginning & End.

Bowing head
This act shows humility and shame. Jesus controls water and sea. He changes water to wine (John 2), he controls the sea
(Matt 8:25), he walks over water (Matt 14:25), he directs fish into the net (John 21/Luke 5). But here he humbly asks for water. He bows down in shame as he has taken all our sins upon him (John 1:29).

He gave up His spirit
Neither the Romans nor Jews took the life of Jesus, He gave up His spirit, also emphasized in the 7th sentence on the cross where he submits the spirit in Gods hands. In John 10 & 19, Jesus says only He can control His life. This proves that He allowed things to happen to Him and He Himself gave up His spirit as per Gods Will. Similarly we must also yield to Gods Will.
John 19:11 Jesus: You could have no power at all against Me unless it had been given you from above.
John 10:10 I have come that they may have life, and that they may have it more abundantly.
11 “I am the good shepherd. The good shepherd gives His life for the sheep.
15 As the Father knows Me, even so I know the Father; and I lay down My life for the sheep.
17 My Father loves Me, because I lay down My life that I may take it again.
18 No one takes it from Me, but I lay it down of Myself. I have power to lay it down, and I have power to take it again.
This command I have received from My Father.”