What is the difference between bring and take?

The choice depends on the direction of movement relative to where the speaker is, or where the speaker imagines being.

Bring is movement toward the reference point. Take is movement away from it.

Bring the report to my office. — I am in the office; the movement is toward me. Take the report to her office. — movement away from me.

The same object and the same journey can require either word depending on who is speaking and from where. If you are at home and calling a colleague at the office, you say bring it here if you are at the office and take it there if you are not.

The reference point does not have to be your physical location. Speakers routinely adopt the listener's viewpoint out of politeness — shall I bring anything to the party? projects you into the host's position, and is entirely standard.

The same logic governs come and go. Come is toward, go is away. I'm coming to your house adopts the listener's location; I'm going to the shops does not.

This is one of the few English distinctions genuinely difficult for learners, because many languages do not encode direction in the verb at all and rely on separate words for here and there.

In some dialects, notably parts of the American South and Ireland, bring is used in both directions, and that is a dialect feature rather than an error within those varieties.

For the past tenses: bring/brought/brought and take/took/taken. Brang is not standard.

A related pair, fetch, means to go and return with something — a round trip, incorporating both directions in one word. Fetch the post means go to it and come back, which neither bring nor take conveys alone.