Hear, hear! (not here, here)
It sometimes seems as if the proper use of English language has fallen by the wayside, given how certain phrases and words are so commonly used in error. However, all is not lost, and every now and then we spare a moment to elaborate on one or two such errors, hoping to steer the good ship Grammar back on the right course again.
And we hear you say, "hear, hear"! Indeed, we concur. Of course, far too often the phrase which people write (obviously it matters not at all when speaking, as each version sounds the same) is "here, here", which is just plain old wrong.
"Hear, hear" is correct, and "here, here" is completely wrong.
So, first things first. The word hear is something you do with your ears - you listen. Although it may be used in many ways, it always refers to listening in some manner.
Reference: https://www.merriam-webster.com/dictionary/hear
On the other hand, the word here is most often used when referring to a place (e.g. "right here", or "not there, but here", etc). Here can also be used in other ways too though, such as "Yes, here I am willing to agree with you."
Reference: https://www.merriam-webster.com/dictionary/here
Nonetheless, although the word here may be used in many ways, "hear, hear" is not one them!
The phrase, "hear, hear", has a long history, and dates all the way back to the seventeenth century (1689 in fact!). It's used to endorse or offer support or agreement to what has previously just been said by a speaker, and is often used during gatherings of people to garner applause.
Here's an example of how it's often [correctly] used:
Speaker 1: (finishes speech to audience)
Speaker 2: "What a wonderful speech by my colleague. His leadership is without equal."
Audience member: "Hear, hear"!
Rest of audience: Applause.
If you ever get confused about which word, hear or here, to use, just remember that hear is something you do with your ear, and that's what the phrase "hear, hear" is all about - having listened to a speaker and then encouraging endorsement.