Point of View is absolutely not the same as Voice. In First Person Voice or in Third Person Voice, the point of view can migrate from person to person. It is, literally, the point from which you view the story. And that is not always the same as the point from which the cast of characters views it.
You create the point of view by shining a spotlight on the characters involved in the action. You create the situation where the reader has to follow 'these people', not 'those people'.
The problem is that new authors become confused. And this is especially true when writing in the first person. Remember, that is a voice, not a point of view. They think that the point of view is always the same as the person who is telling the story. And in first person voice that person is often also the narrator.
Let me show you an example. It's a pair of dialogue passages with some descriptive prose:
If there'd been somewhere to sit down I'd have had to, just to take it all in!
This was going to be fun!
Tom turned to me on the foredeck while Hazel was explaining it all. "You're loving this, aren't you!"
"Yes, oh yes! Almost as much as I love you. Though it's a close call right now!"
"Oh that's so cute," Hazel said. "I've known there's no hope for girls with Tom for ages. I'm so glad you've found a good looking boyfriend, Tom!"
"Wait? What? How? And yes, he's adorable..."
"Later, matey, we're going to connect this thing up and fly it. Then we get to drop it and re-pack it."
The person speaking, Jerry, is also our narrator. It's clear that it is his voice being used and that the tale is, in this segment, told with him as the pivotal point for the Point of View.
Following that piece, immediately after it, comes this snippet:
"Ok, now, how?" We'd flown and dropped the big kite a couple of times, and Tom was below repacking it with Hazel. They almost had time for a conversation amid the rustling of their fighting with the huge sail in the small cabin.
"Well," she started, "It's not that I've drooled over you and got nowhere, exactly. And don't look hurt with those puppy dog eyes, they fool no-one! It's that you've only ever treated me as someone you get on well with, not someone you might want to climb into bed with. Not that I want anyone to climb into bed with me, you understand, but it's nice to feel wanted."
"Would you be upset if I told you I'd tried to be attracted to you?"
"In an odd way a bit flattered, but in most ways slightly weirded out!"
"Won't be telling you that then!"
"Nah, best not. Anyway this is all packed. Let's go up and see what dad's got in mind."
Where is the pivot for the point of view now? Something has changed in the dynamic, but it's subtle. We've arrived 'below' with Tom and Hazel. Jerry, our narrator, remains out of the scene entirely, though he appears as part of 'we' in the first paragraph, but the point of view has switched to Tom and Hazel. Jerry has 'overheard' something he really couldn't hear. He wasn't present.
We could spend a load of time wondering if that's been done well or could be done better. We could debate it, but it's happened. The story has been made to move into an area detached from the first person narrator in a way new authors think to be impossible, yet is easy to do. How was it done?
That question was homework for you.
If this can be done with first person, which is harder, it can be done with third person. The mechanisms are the same. Just think of yourself as a spotlight operator. You can turn the spot onto any character and give us the story with them in sharp focus.
But you have to control it. Switching hither and yon too often will confuse your readers and they will give up and read something else. Just think of a theatre audience trying to follow a spotlight as it flits from place to place too rapidly. The audience gives up.