Do you need to be a British citizen and do you just sign up once you are 18 years. Then you go for basic training

Hi Adewale, Currently if you are British, Irish, or from a Commonwealth country you can apply to join the British Army. You don’t need UK citizenship or residency. Places and roles for Commonwealth soldiers are limited but once you register your interest the recruitment team will contact you and let you know your options. If you want to naturalise while you're serving, you'll need to pay all the costs and make sure you meet the Home Office's requirements. Your service can count towards the residency part of the requirements. I hope this helps but please feel free to come back to me if you’d like to know more. Katie

Thanks. And even underage Application too ?

You must be at least 16 years old to join the Army as a soldier. You can start your application when you are 15 years and 7 months. If you are under 18 you will need parental consent to join. To join as an officer you must be at least 18 years old. To enter Welbeck, you must be between the ages of 15 years 6 months and 17 years and 6 months.