Good afternoon subhan109,
Welcome to the Apple Support Communities!
I understand you would like to customize what controls you see in the Touch Bar on your Mac. The Touch Bar is going to display the application that you are currently using. If you are using the Chrome browser to view videos on YouTube, that is why you are seeing Chrome in the Touch Bar. You can try quitting Chrome and iTunes and restarting your computer to refresh it. You can also update your computer to macOS Mojave version 10.14.5 and see if there are updates to Chrome and other third-party apps as well. The resource below explains how to customize the Touch Bar. I've highlighted some key information here for you. Click on the link for complete details.
How to use the Touch Bar on your MacBook Pro
"In any app that supports customization (such as Finder), Select View > Customize Touch Bar. Touch the Control Strip region of the Touch Bar to switch to Control Strip customization. Then use your cursor to drag items that you want from the display down into the Control Strip. Drag items left and right within the Control Strip to rearrange them, or drag them up and out of the Touch Bar to remove them. Tap Done in the Touch Bar or click Done on the screen when you finish.
You can also enter Control Strip customization mode by clicking "Customize Control Strip" in the Keyboard section of System Preferences."
Take care.