There are lots of QR code generators on the internet but you should look for the most reliable provider to use. For instance, I used this website
https://www.qr-code-generator.com/[/li][/list]
Sounds like a privacy nightmare. If you want to generate QR coded addresses, use the internal function of a wallet software, like Electrum.
Hence it generates a QR code that you can download as an image.
And you should verify that the QR code actually corresponds to your address and not to theirs.
So as when your bitcoin address is requested you can just send the image for scan to prevent your Bitcoin address from being tempered with.
What prevents someone from tampering your QR coded address?
In summary, it provides no extra security, introduces more complexity, and is worse privacy-wise.