How to add CMS block Programmatically using Patch?

Whenever we deal with content in Magento, we have requirements where we want to provide the power of changing content to the admin but at the same time, we want to display that block's content somewhere according to the developer's code. OR if you want to create multiple blocks with Magento setup, then you can use the below approach to create them.

Create a Patch file in your module at MageInsight/ModuleName/Setup/Patch/Data/AddCmsBlock.php

<?php
namespace MageInsight\ ModuleName\Setup\Patch\Data;

use Magento\Cms\Model\BlockFactory;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Framework\Setup\Patch\DataPatchInterface;
use Magento\Framework\Setup\Patch\PatchRevertableInterface;
use Magento\Store\Model\Store;

class AddCmsBlock implements DataPatchInterface, PatchRevertableInterface
{

const CMS_BLOCK_IDENTIFIER = 'block_name';

/**
* @var \Magento\Framework\Setup\ModuleDataSetupInterface
*/
private $moduleDataSetup;

/**
* @var BlockFactory
*/
private $blockFactory;

/**
* InstallOrderStatusesAndInitialSalesConfig constructor.
* @param \Magento\Framework\Setup\ModuleDataSetupInterface $moduleDataSetup
* @param BlockFactory $salesSetupFactory
*/
public function __construct(
\Magento\Framework\Setup\ModuleDataSetupInterface $moduleDataSetup,
BlockFactory $blockFactory
) {
$this->moduleDataSetup = $moduleDataSetup;
$this->blockFactory = $blockFactory;
}

/**
* @inheritDoc
*/
public function apply()
{
$this->moduleDataSetup->startSetup();
$this->blockFactory->create()
->setTitle('Test Block')
->setIdentifier(self::CMS_BLOCK_IDENTIFIER)
->setIsActive(true)
->setContent('Hello')
->setStores([Store::DEFAULT_STORE_ID])
->save();

$this->moduleDataSetup->endSetup();
}

/**
* {@inheritdoc}
*/
public function revert()
{
$sampleCmsBlock = $this->blockFactory->create()->load(self::CMS_BLOCK_IDENTIFIER, 'identifier');
if ($sampleCmsBlock->getId()) {
$sampleCmsBlock->delete();
}
}

/**
* @inheritDoc
*/
public static function getDependencies()
{
return [];
}

/**
* @inheritDoc
*/
public function getAliases()
{
return [];
}
}

Once you add this file, you need to execute the command for the setup upgrade. 

php bin/magento setup:upgrade
php bin/magento cache:clean

And after the command execution is done successfully you can see your CMS block in the admin.