Hello,
if you are referring to the names of the various cart fields, you can find them in the Content Language in Step 1 - Settings ---> General Information.

Keep in mind that changing the default text will apply to all projects in that language, so depending on the change you want to make you may want to create a custom language to use for a specific project.
You can do so by selecting a language and clicking the first icon on the left above the language list.

Eric

I have created a shopping cart field that can be converted from English to Chinese. I want to modify the text, field color and font size of the CART page.

Hello,
the text can be modified as I mentioned above, but the rest, if I have not misunderstood your request, would need custom code to be modified specifically in that page.

Eric