Hi I'm having a big problem with the images uploaded on the blog when sharing on facebook the image is not visible there ON FACEBOOK.
What can I do to make them appear?

Link: https://www.soboladas.co.mz/blog/article/reu-agradece-ao-chefe-do-estado-em-tribunal-b11

Does not seem you have og/meta tags generated.
look on source code here:
view-source:https://plugins2.abprofitrade.eu/blog/article/hired-people-are-awesome-b6

<!-- Facebook Open Graph Tags-->
<meta property="og:title" content="Hired people are awesome - Osclass Plugins 2 - Classifieds demo site" />
<meta property="og:site_name" content="Hired people are awesome - Osclass Plugins 2 - Classifieds demo site"/>
<meta property="og:url" content="https://plugins2.abprofitrade.eu/blog/article/hired-people-are-awesome-b6" />
<meta property="og:description" content="Nunc elementum neque velit, id lobortis diam pretium id." />
<meta property="og:locale" content="en_US" />
<meta property="og:image" content="https://plugins2.abprofitrade.eu/oc-content/plugins/blog/img/blog/6.jpg" />

<!-- Twitter Tags-->
<meta name="twitter:card" content="summary" />
<meta name="twitter:site" content="@Anonymous" />
<meta name="twitter:title" content="Hired people are awesome - Osclass Plugins 2 - Classifieds demo site" />
<meta name="twitter:description" content="Nunc elementum neque velit, id lobortis diam pretium id." />
<meta name="twitter:image" content="https://plugins2.abprofitrade.eu/oc-content/plugins/blog/img/blog/6.jpg" />

How to generate this? or where to put?

I am not sure right now, check general osclass settings if you are using latest version - structured data.

I'm using the latest osclass version and I can't find it in the settings - structured data

Settings > general.
Structured data
Allow osclass to generate structured data (microdata) for google, facebook, twitter, ...

thank you my friend it worked

Glad to hear that