If you want to practice a specific opening, you can choose your color in unrated games!
In all rated games on Chess.com, the color is chosen at random!
Although it might feel like you’re getting a lot of games in a row as one color, it will balance out to around 50%. You can check your stats page to see how many games you’ve had with each color, and confirm that it’s about 50% each.
How To Choose Your Color In Unrated Games
This kind of game may take longer to find a match, because not as many people want to play unrated games.
Hover over Play in the left side menu and select Play
Click the Custom dropdown
Choose your preferred time and game type
Untoggle the rated option
After turning off the rated option, you'll be able to pick your color - Choose your color, then click Play to search for a game
Alternatives To Choosing Color
Another way to choose your color without waiting for a match is to play against the computer.
Check out this article to learn how to play a bot: How can I play against the Chess.com computer?