Magento 2: how to get Model in Block

Override constructor in your block class and add your class factory as dependency.

public function __construct(
    \Magento\Backend\Block\Template\Context $context,
    \Vendor\Exple\Model\StandardFactory $modelFactory,
    array $data = []
) {
      $this->modelFactory = $modelFactory;
      parent::__construct($context, $data);
}

function someMetod() {
    $model =  $this->modelFactory->create();
}

You can instantiate your model by using constructor. You can call it by ObjectManager directly but passing by constructor is the best approach.

Example by using constructor

protected $customer;

/**
 * @param \Magento\Framework\App\Action\Context $context
 * @param \Demo\HelloWorld\Model\Customer $customer
 */
public function __construct(
    \Magento\Framework\App\Action\Context $context,
    \Demo\HelloWorld\Model\Customer $customer
) {
    $this->customer = $customer;

    parent::__construct($context);
}

$this->customer is your model instances.

Hope this helps.

You can use below code to call the model from anywhere

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$model = $objectManager->create('\Namespace\Modulename\Model\Modelname');