Many people may take their birth certificate, or similar official papers, for granted - hidden in a drawer and rarely seeing the light of day - but for those without one, it can lead to a shadow life or an uncertain existence.
This is thought to affect millions of people around the world, described as stateless, and 25-year-old South African Arnold Ncube is one of those.
Because he has no state-issued documents, washing cars in the backstreets of Thembisa township near Johannesburg is one of the few ways he can make a living.
He was born in Johannesburg and his father is South African, qualifying him for citizenship here. But when he tried to register for secondary school, he realised he didn't have a birth certificate.
Having been abandoned by his parents - his dad left before he was born and his mum when he was 14 - he could not prove his status.
It's a painful thing, he says. You're basically invisible. You don't exist. It's like you're living in the shadows. You don't have a bank account, you can't apply for a decent job that you can earn a living with.
He adds that he tries to stay positive but it's been challenging.
When I see my peers, they are done with school now. Whereas I couldn't study further. It's a lot. Depression was once my friend.
Arnold is one of at least an estimated 10,000 stateless people living in South Africa who, despite being born here, are struggling to prove their nationality and access public services.
There are no official statistics available on stateless people here because they tend to slip through the cracks. So the figures are based on estimations by organisations like the UN's refugee agency, the UNHCR and civil rights organisations.
With no citizenship, stateless people cannot get documents and struggle to get access to basic necessities including education and healthcare.
Statelessness is caused by many factors, including administrative barriers and poor record-keeping. As a result the real number of stateless people is hard to gauge in many parts of the world.
Human rights lawyer and advocate Christy Chitengu used to be stateless herself.
She only got South African citizenship three years ago with the help of the organisation Lawyers for Human Rights who worked on her case for free.
I found out I was stateless at the age of 17. My high school principal called me into her office and told me that she didn't have any documents for me and that she didn't understand how I'd gotten into the school, she tells the BBC near her home in northern Johannesburg.
Christy says that when she found out she was stateless she looked into taking her parents' nationality but it was too late.
Statelessness is not just an issue here, it is a huge global problem.
There's an estimated 4.5 million stateless people around the world. Some say the figure could even be as high as 15 million.
Experts believe tackling the problem requires policy changes, including allowing refugees to register their children where they're born, and giving mothers the right to pass their nationality to their children.
