I created a site with Joomla3.
When I click on the tags link on a blog post, it shows a page of articles but without a module.
I want to add a module to this page.
The display of modules on a Joomla website is generally controlled via the "Menu Assignment" tab when editing the module in Module Manager.
Clicking on a tag link may take you to a different page so that modules displayed on the original page are no longer displayed on the new page.
Module assignment options are:
You might be able to solve your issue if you change the module assignment option to "On all pages" or "On all pages except those selected" with an appropriate selection.