Magento2 : Create Config and Get system config value

Create Configration :
Create file inside etc/adminhtml/system.xml.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="tabid" translate="label" sortOrder="600">
            <label>TabLabel</label>
        </tab>
        <section id="subtab_id" translate="label" type="text" sortOrder="100" showInDefault="1" showInWebsite="1" showInStore="1">
            <label>Sub Tab Name</label>
            <tab>Sub Tab Name</tab>
            <resource>NaeSpace_ModuleName::config</resource>
            <group id="fieldName" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Setting</label>
                <field id="fieldPath" translate="label" type="text" sortOrder="20" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Text Field Name</label>
                </field>
            </group>
        </section>
    </system>
</config>

Value will store in core_config_data table.in path column it will be tabid/fieldName/fieldPath.And value column store saved value .
Get system config value in Magento2:

protected $_scopeConfig;  
public function __construct(\Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig) {
        $this->_scopeConfig = $scopeConfig;
}
public function methodName()
{
    $configValue =  $this->_scopeConfig->getValue('tabid/fieldName/fieldPath', \Magento\Store\Model\ScopeInterface::SCOPE_STORE); 
}

First argument is the value which we need from system configuration and the Second argument is the Store scope.