#app/code/Sistel/Transzuri/etc/config.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../Magento/Store/etc/config.xsd">
    <default>
        <carriers>
            <sistel_transzurishipping>
                <active>0</active>
                <sallowspecific>0</sallowspecific>
                <price>0</price>
                <model>MagePsychoCustomshippingModelCarrierTranszurishipping</model>
                <name>Transzuri</name>
                <title>Transzuri</title>
                <specificerrmsg>This shipping method is not available. To use this shipping method, please contact us.</specificerrmsg>
            </sistel_transzurishipping>
        </carriers>
    </default>
</config>

#app/code/Sistel/Transzuri/Model/Carrier/Transzurishipping.php
<?php

namespace SistelTranszuriModelCarrier;

use MagentoQuoteModelQuoteAddressRateRequest;

/**
 * @category   MagePsycho
 * @package    MagePsycho_Customshipping
 * @author     magepsycho@gmail.com
 * @website    http://www.magepsycho.com
 * @license    http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */
class Transzurishipping extends MagentoShippingModelCarrierAbstractCarrier implements
    MagentoShippingModelCarrierCarrierInterface
{
    /**
     * @var string
     */
    protected $_code = 'sistel_transzurishipping';

    /**
     * @var bool
     */
    protected $_isFixed = true;

    /**
     * @var MagentoShippingModelRateResultFactory
     */
    protected $_rateResultFactory;

    /**
     * @var MagentoQuoteModelQuoteAddressRateResultMethodFactory
     */
    protected $_rateMethodFactory;

    /**
     * @param MagentoFrameworkAppConfigScopeConfigInterface $scopeConfig
     * @param MagentoQuoteModelQuoteAddressRateResultErrorFactory $rateErrorFactory
     * @param PsrLogLoggerInterface $logger
     * @param MagentoShippingModelRateResultFactory $rateResultFactory
     * @param MagentoQuoteModelQuoteAddressRateResultMethodFactory $rateMethodFactory
     * @param array $data
     */
    public function __construct(
        MagentoFrameworkAppConfigScopeConfigInterface $scopeConfig,
        MagentoQuoteModelQuoteAddressRateResultErrorFactory $rateErrorFactory,
        PsrLogLoggerInterface $logger,
        MagentoShippingModelRateResultFactory $rateResultFactory,
        MagentoQuoteModelQuoteAddressRateResultMethodFactory $rateMethodFactory,
        array $data = []
    ) {
        $this->_rateResultFactory = $rateResultFactory;
        $this->_rateMethodFactory = $rateMethodFactory;
        parent::__construct($scopeConfig, $rateErrorFactory, $logger, $data);
    }

    /**
     * @param RateRequest $request
     * @return MagentoShippingModelRateResult
     * @SuppressWarnings(PHPMD.UnusedLocalVariable)
     */
    public function collectRates(RateRequest $request)
    {
        if (!$this->getConfigFlag('active')) {
            return false;
        }

        /** @var MagentoShippingModelRateResult $result */
        $result = $this->_rateResultFactory->create();

        $shippingPrice = $this->getConfigData('price');

        $method = $this->_rateMethodFactory->create();

        $method->setCarrier($this->_code);
        $method->setCarrierTitle($this->getConfigData('title'));

        $method->setMethod($this->_code);
        $method->setMethodTitle($this->getConfigData('name'));

        $method->setPrice($shippingPrice);
        $method->setCost($shippingPrice);

        $result->append($method);

        return $result;
    }

    /**
     * Get allowed shipping methods
     *
     * @return array
     */
    public function getAllowedMethods()
    {
        return [$this->_code => $this->getConfigData('name')];
    }
}

#app/code/Sistel/Transzuri/etc/adminhtml/system.xml
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../Magento/Config/etc/system_file.xsd">
    <system>
        <section id="carriers" translate="label" type="text" sortOrder="1" showInDefault="1" showInWebsite="1" showInStore="1">
            <group id="sistel_transzurishipping" translate="label" type="text" sortOrder="2" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Transzuri</label>
                <field id="active" translate="label" type="select" sortOrder="1" showInDefault="1" showInWebsite="1" showInStore="0">
                    <label>Enabled</label>
                    <source_model>MagentoConfigModelConfigSourceYesno</source_model>
                </field>
                <field id="title" translate="label" type="text" sortOrder="2" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Title</label>
                </field>
                <field id="name" translate="label" type="text" sortOrder="3" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Method Name</label>
                </field>
                <field id="price" translate="label" type="text" sortOrder="4" showInDefault="1" showInWebsite="1" showInStore="0">
                    <label>Shipping Cost</label>
                    <validate>validate-number validate-zero-or-greater</validate>
                </field>
                <field id="specificerrmsg" translate="label" type="textarea" sortOrder="80" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Displayed Error Message</label>
                </field>
                <field id="sallowspecific" translate="label" type="select" sortOrder="90" showInDefault="1" showInWebsite="1" showInStore="0">
                    <label>Ship to Applicable Countries</label>
                    <frontend_class>shipping-applicable-country</frontend_class>
                    <source_model>MagentoShippingModelConfigSourceAllspecificcountries</source_model>
                </field>
                <field id="specificcountry" translate="label" type="multiselect" sortOrder="91" showInDefault="1" showInWebsite="1" showInStore="0">
                    <label>Ship to Specific Countries</label>
                    <source_model>MagentoDirectoryModelConfigSourceCountry</source_model>
                    <can_be_empty>1</can_be_empty>
                </field>
                <field id="showmethod" translate="label" type="select" sortOrder="92" showInDefault="1" showInWebsite="1" showInStore="0">
                    <label>Show Method if Not Applicable</label>
                    <source_model>MagentoConfigModelConfigSourceYesno</source_model>
                </field>
                <field id="sort_order" translate="label" type="text" sortOrder="100" showInDefault="1" showInWebsite="1" showInStore="0">
                    <label>Sort Order</label>
                </field>
            </group>
        </section>
    </system>
</config>