For scan a QR code, which app do I need?

[PeterBushMan]

1) For scan a QR code, which app do I need?

1) How to scan a QR code?

[swansont]

You should use the search function on the site where you get apps for your device.

[geordief]

I don't need any app on my phone as it came included in one of the android upgrades.

I just have to turn on the  camera ,point it at the QR code and the website connected to the QR code pops up on the screen.

I have no idea if this procedure works differently with non android phones.

[Sensei]

In Android 5 and below, you need to install a 3rd party app. Pick up one from the Google Play Store.

In Android 6 and 7 you can enable "Now On Tap". If you don't want to, or in your country it is not available, install the 3rd party app like above. 

In Android 8 and later, QR code reader is built-in a camera app, but you might have to enable it in Settings.

Different device manufacturers have different camera apps, so search the web for "how to enable qr codes " plus your device model name and OS version.

Edited September 27, 2021 by Sensei

[Ghideon]

8 hours ago, PeterBushMan said:

1) For scan a QR code, which app do I need?

1) How to scan a QR code?

It depends on what the code represent. As said above many phones can recognise a QR code by using the native camera app. Interpreting the QR code and then triggering the correct action may require scanning the QR code with the applicable 3rd party application. 

[PeterBushMan]

My phone is very old.

[SergUpstart]

If you want to write your own program for reading QR codes, for example in C#, you can use the ZXing library

[Ghideon]

30 minutes ago, PeterBushMan said:

My phone is very old.

Ok. Very old phones have no camera. So a newer phone may be required to solve your issue.

(You may get more helpful responses if you provide more context)

[Sensei]

On 9/30/2021 at 11:28 AM, PeterBushMan said:

My phone is very old.

Too ambiguous.

"Very old" for most modern people are devices of 4 years or more.

Give the manufacturer and model name, operating system version, etc. etc.

[exchemist]

On 9/30/2021 at 10:28 AM, PeterBushMan said:

My phone is very old.

Then it is unlikely to be able to run many of today's apps in any case.

This is certainly the case for my 7 yr old G3 iPhone. It does have a camera but it is full of dust inside and takes terrible pictures, so it would have no chance of scanning a QR code, even if it could run the app.