I want Firefox as my browser but google don’t allow
Tell me why I am forced to use google as my browser?
Are you talking about the home page? https://support.mozilla.org/en-US/kb/how-to-set-the-home-page
Or the search engine? Type about:preferences#search<enter> in the address box. You can select any search engine to be your default from here.
You can also remove any engine from here.
New Tab Settings https://addons.mozilla.org/firefox/addon/new-tab-override/