“here we go”, You could say this when you are starting out on an errand or a trip, for example, when you put your car or bicycle in motion. Alternatively, you could say it casually when something good and unexpected happens, like finding something you had lost. “here you go” You could say this when giving something such as money to another person. “there we go” You could say this casually when something good and unexpected happens, like succeeding at a video game, or solving a mechanical problem. “there you go” Pretty much the same as "here you go". You could say this when giving something such as money to another person.

These a very colloquial expressions not easy to explain. It depends on context. If you order something from me and I hand it to you, you can say any of the following: “here we go”, “here you go” If I did not understand something at first, but later do. The other person may say: “there we go” “there you go” “here we go again" something being repeated or repetitious

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