By default, Firefox does not come with translation features. However, you can easily add such a feature by installing an add-on of your choice.
Language Support Extensions
You can also explore other language support extensions on addons.mozilla.org.
You can also search for translation tools that are part of Mozilla's Recommended Extensions program.
These extensions are not Mozilla products.
Please see our Tips for assessing the safety of an extension
before installing software developed by third party developers. If you need support for any of these extensions, please contact their respective authors.