Genesis 1:31 (WEB), "God saw everything that he had made, and, behold, it was very good. There was evening and there was morning, a sixth day." This ending statement is made after each creative day. But on the Seventh day the statement of "there was evening and there was morning, a seventh day" is not made by Elohim Yahweh. Why? What's the meaning or implication of this? (India)

The seventh day is not yet finished. Mankind has been living through the seventh day.  As you noted, Yahweh uses, “there was evening and there was morning” at the end of each of the six creative days.  Yahweh blessed the seventh day, and He is now resting from his creative work. During this seventh day, mankind is learning the lessons of sin and disobedience.  

The seventh day will finish with the full establishment of Christ’s kingdom and the bringing of mankind back into harmony with the Heavenly Father. 1 Corinthians 15:24, 25, 28 (CSB), “Then comes the end (of the seventh day) when he hands over the kingdom to God the Father, when he abolishes all rule and all authority and power. For he must reign until he puts all his enemies under his feet…When everything is subject to Christ, then the Son himself will also be subject to the one who subjected everything to him, so that God may be all in all.”