To obtain British citizenship you must go through the naturalization process. This can be done in two ways: by renouncing our current nationality or by obtaining dual nationality. It should be borne in mind that some countries do not allow either of these two cases, so it is best to check with the Embassy or Consulate of your current country. You have all the information in: «Tips, documentation and requirements to travel to the UK«.
You have all the information in: "Tips, documentation and requirements to travel to the UK".