The method I employ to generate a vCard QR Code is to export a contact directly from my iPhone Contacts App, then upload that exported .vcf into a QR Code Generator online that I trust. The vCard exported directly from your iPhone will contain everything about that individual (name, number, email address, company, etc) and will keep all of that data intact. So, when someone scans your QR Code, it is imported into their contact list immediately without the need for any applications or manually typing in any of the contact's particulars; much lower chance of failure than other methods. This is the method most often utilized in a practical format.
My preferred way of sharing contact details is using the built-in Contacts app and Apple's Shortcuts app. Why do I prefer this? It is native to iOS which makes it quick and easy to use and it does not come with any third-party privacy risks. Here is my process for using a vCard and QR code for sharing contacts on my iPhone: 1. Securely save or open the contact you want to share. 2. Use a simple shortcut that creates a vCard from the contact you're sharing and generates a QR code. 3. Save the QR code to your photos or share it immediately. This method works really well because the QR code is continually updated with the real-time data from the contact (i.e. phone numbers, email addresses, company name, website, etc) and you never have to manually enter anything into your contact list. There are no broken links to worry about and the QR code scans perfectly on both iOS and Android devices. I try to avoid using web-based QR code generators because if I have to, I want to have fewer steps, more control over my contact data and no hidden costs for using an app. When I want to share contact information via vCard, I find that using built-in applications is the way to go.