How to match up colors?

We all have different styles and tastes and color for me is such a personal choice but that being said perhaps this article will help - https://freshome.com/2013/10/22/10-easy-ways-mix-match-patterns-home/

Well, your question is really open-ended and I don't know what colors you want to match up, or where you want to put these colors. I can only point you in the direction of an artist's color wheel which you can buy for $5.99 in an art or craft store. By turning the inner dial you will find all the color combinations you could ever dream of.

If you want to match paint colors, you can take a paint sample to the hardware store. They can find paint to match it exactly :)

The color strips from paint makers are a great to see which colors look good with what, whether you want accent colors or complementary colors.

You need to be a little more specific with your questions. Match up paint colors on a wall or make paint colors to furniture/decor? Do you prefer bold or cool hues? Neutrals? What style décor do you have? Modern, Victorian, Country? What room is it for and what size is the room? Etc etc. Need more info in order to give a proper answer.

Do you need to match some existing paint? You can take a sample to a paint store and they can match it perfectly.

I once took a piece of chipping off paint to Lowe's and they matched it so well, you couldn't tell what was freshly painted. The room was retail space, so it was enormous and the top third needed painting to match the bottom two-thirds.