If you want to load any extension’s block without use layout xml, we can use the widget to make that.

For example: we want to load block type “Magento\Newsletter\Block\Subscribe”  – it will been call to block class file “vendor/magento/module-newsletter/Block/Subscribe.php”

Please follow as this:

Widget options:

Widget Title: Input the block title will show or hide on frontend.

Enable Collapse: Will show block as collapse (toggle content) when view the block on mobile view or not.

Addition Class: Custom Block css class, use for custom style for block

Widget Box Style: Use bootstrap 3 css class for box. With there options: Default, Primary, Danger, Info, Warning, Highlighted, Nopadding, No-margin

Block Type: Input the block type (it will call to module block class), same way of layout xml are calling.

On layout xml, the block are calling as this:

<block class=”Magento\Newsletter\Block\Subscribe” name=”form.subscribe” as=”subscribe” before=”-” template=”Magento_Newsletter::subscribe.phtml”/>

Block Name: input the name for the block as you want.

Block Parameters: You can input there param will use on the block. example:

template=’Magento_Newsletter::subscribe.phtml’