"Vaccine passports" are digital or paper documents that show you were vaccinated against Covid-19 and could help you get into a growing number of places.

What they look like and why you might want one depend on where you live, but more private venues, workplaces and governments are requiring proof of vaccination in public settings.

Europe and US states like California and New York created official digital credentials that let you verify your Covid-19 immunisation record and convert it into a scannable QR code you can pull up on your cell phone.

Most places that require vaccination proof also accept simpler options, such as the paper card noting the dates of your shots from the US Centers for Disease Control and Prevention. In the US, showing a photo of that card on your phone will usually suffice.

Read: Bangladesh to receive 60 lakh more Pfizer vaccine doses in Aug: Minister

Denmark, Greece, France, Italy, some Canadian provinces and the US cities of New Orleans, New York and San Francisco are among the places that have vaccination requirements to get into places like indoor restaurants or theatres. Enforcement varies, and many places also accept a recent negative test for the virus, a partial vaccination or proof that you previously recovered from the disease.

Even without government mandates, more businesses in countries where vaccines are readily available are starting to ask for proof that you got the shots, so long as their local governments have not blocked them from doing so.

Officials around the world were initially reluctant to mandate vaccines, but some now hope doing so will persuade more people to get the shots. Businesses requiring proof of vaccination say they are trying to make customers and employees feel safe.

Read: US regulators give full approval to Pfizer COVID-19 vaccine

Protesters in France and elsewhere have criticised vaccine mandates as invasive and restricting freedom of movement. Privacy advocates have raised concerns about getting people in the habit of having their phones scanned wherever they go, and generally favour options that will not be tracked, such as a paper record or a digital copy in your phone that can be shown at the door.