If I flip a coin n times how many different combinations are there?

For example if a coin is flipped 3 times I know how to calculate all the possible outcomes. I don't understand how I reduce that count to only the combinations where the order doesn't matter.

I know there's 8 permutations but how do you reduce that count to 4? {HHH,TTT,HTT,THH}

I've tried thinking about the combinations formula with repetition, the product rule, the division rule.

For example if a coin is flipped 3 times I know how to calculate all the possible outcomes. I don't understand how I reduce that count to only the combinations where the order doesn't matter.

I know there's 8 permutations but how do you reduce that count to 4? {HHH,TTT,HTT,THH}

I've tried thinking about the combinations formula with repetition, the product rule, the division rule.