This verse describes a miraculous event in the story of the floating axe head. Let's break it down:

Context: A group of prophets was building a larger place to live. While one was chopping down a tree, the axe head flew off the handle and landed in the water. It was a borrowed axe, causing the prophet great distress because he would have been indebted to the lender.
"He said, 'Take it.'": This "He" refers to the prophet Elisha, who had the power of God. Elisha asked where the axe head had fallen. He then threw a stick into the water at that spot. Miraculously, the axe head floated to the surface. Elisha then commanded someone to "take it."
"So he put out his hand and took it.": This is simple obedience and the completion of the miracle. The person (likely the prophet who lost the axe head) followed Elisha's instruction. He reached out and retrieved the axe head that was now floating.

Meaning/Significance:

God's Power: The verse highlights God's power through Elisha, demonstrating His ability to perform the impossible. He can even defy the laws of physics and cause iron to float.
Compassion and Restoration: The miracle shows God's compassion for the prophet's distress. He restored what was lost and saved him from the potential financial burden of replacing the borrowed axe.
Obedience: The prophet's simple act of putting out his hand and taking the axe head underscores the importance of obedience to God's instructions. He trusted Elisha's word and acted on it.
Small Needs Matter: The story shows that God cares about even the small, practical needs of His people. It's not just about grand miracles, but also about the everyday concerns of those who are faithful to Him.

In essence, this seemingly simple verse encapsulates a powerful demonstration of God's ability to provide, restore, and care for His followers. The act of "taking it" is an act of faith and acceptance of God's provision.