I want to add custom button on node page.

I tried with hook_node_view but it didn’t show up.

like this:

function mymodule_node_view(array &$build, EntityInterface $entity, EntityViewDisplayInterface $display, $view_mode) {  $build['mybutton'] = [   '#type'       => 'button',   '#name'       => 'mybutton_name',   '#value'      => t('Click Here'),   '#attributes' => [ 'class' => 'button button--primary'],   '#weight'     => -11, ]; 

}

What am I doing wrong?

EDIT:

Here is the template

{# /**  * @file  * Display Suite 2 column stacked template.  *  * Available variables:  * - outer_wrapper: outer wrapper element  * - header_wrapper: wrapper element around header region  * - left_wrapper: wrapper element around left region  * - right_wrapper: wrapper element around right region  * - footer_wrapper: wrapper element around footer region  * - attributes: layout attributes  * - header_attributes: attributes for header region  * - left_attributes: attributes for left region  * - right_attributes: attributes for right region  * - footer_attributes: attributes for footer region  * - header: content of header region  * - left: content of left region  * - right: content of right region  * - footer: content of footer region  */ #}  <{{ outer_wrapper }}{{ attributes.addClass('ds-2col-stacked', 'clearfix') }}>    {{ title_suffix.contextual_links }}    <{{ header_wrapper }}{{ header_attributes.addClass('group-header') }}>     {{ header }}   </{{ header_wrapper }}>    <{{ left_wrapper }}{{ left_attributes.addClass('group-left') }}>     {{ left }}   </{{ left_wrapper }}>    <{{ right_wrapper }}{{ right_attributes.addClass('group-right') }}>     {{ right }}   </{{ right_wrapper }}>    <{{ footer_wrapper }}{{ footer_attributes.addClass('group-footer') }}>     {{ footer }}   </{{ footer_wrapper }}>  </{{ outer_wrapper }}>