Yes, the QR code required is not a normal QR code with a link. It should be TLV base64 encoded. It can be done very easily. the values need to be hexed and then combined which will contain ASCII control characters.

If you still don't get it, Luckily, You can use the following package by Salla to generate a QR code from the array.

https://github.com/SallaApp/ZATCA

Make sure to follow the Tag structure provided by the ZATCA (GAZT previously). The package's example has the correct array:

$generatedString = GenerateQrCode::fromArray([
    new Seller('Salla'), // seller name
    new TaxNumber('1234567891'), // seller tax number
    new InvoiceDate('2021-07-12T14:25:09Z'), // invoice date as Zulu ISO8601 @see https://en.wikipedia.org/wiki/ISO_8601
    new InvoiceTotalAmount('100.00'), // invoice total amount
    new InvoiceTaxAmount('15.00') // invoice tax amount
    // TODO :: Support others tags
])->toTLV();

For those who are still using php5 based on https://github.com/SallaApp/ZATCA

/*
 * QR Encoding Functions
 */

function __getLength($value) {
    return strlen($value);
}

function __toHex($value) {
    return pack("H*", sprintf("%02X", $value));
}

function __toString($__tag, $__value, $__length) {
    $value = (string) $__value;
    return __toHex($__tag) . __toHex($__length) . $value;
}

function __getTLV($dataToEncode) {
    $__TLVS = '';
    for ($i = 0; $i < count($dataToEncode); $i++) {
        $__tag = $dataToEncode[$i][0];
        $__value = $dataToEncode[$i][1];
        $__length = __getLength($__value);
        $__TLVS .= __toString($__tag, $__value, $__length);
    }

    return $__TLVS;
}

/*
 * QR Encoding Functions
 */


/*
 * QR Code
 */
$dataToEncode = [
    [1, 'SellerName'],
    [2, 'VATNumber'],
    [3, 'invoiceDatetime'],
    [4, 'AmtwithVAT'],
    [5, 'VATamt']
];

$__TLV = __getTLV($dataToEncode);
$__QR = base64_encode($__TLV);

echo  $__QR;


/*
 * QR Code
 */

1-- Install ZATCA SDK https://zatca.gov.sa/en/E-Invoicing/SystemsDevelopers/ComplianceEnablementToolbox/Pages/DownloadSDK.aspx

2 -- fatoorah validateqr -qr "$__QR"

function einv_generate_tlv_qr_code($array_tag=array()){
    $index=1;
    foreach($array_tag as $tag_val){
        $tlv_string.=pack("H*", sprintf("%02X",(string) "$index")).
                     pack("H*", sprintf("%02X",strlen((string) "$tag_val"))).
                     (string) "$tag_val";
        $index++;                              
    }      
    return base64_encode($tlv_string);
}

Just send you tags values in array to the function and it will return you the TLV content of QRcode

$data_tlv=einv_generate_tlv_qr_code(array($company_name,$vat_reference,$timestamp,$total,$vat);