Templates & Frontend
See Every Module Position in a Joomla Template
You are working with a template someone else built and you need to know what its module positions are called and where they land on the page. Joomla can draw them for you, but the switch is off by default and the reason it is off is worth…
Turn the preview on
Go to System → Templates → Site Templates, open Options, and set Preview Module Positions to Enabled.
Append the parameter
Open any front-end URL with ?tp=1 on the end:
https://example.com/index.php?tp=1Every position is outlined and labelled with the name you would type into a module's Position field. Positions that hold no modules are drawn too, which is the whole point — an empty position is invisible otherwise.
The parameter works on any page, not just the front page. That matters when a template exposes different positions on different views.
Why it ships disabled
The parameter creates a second address for every page on the site. Left enabled on a live site, those addresses can be crawled and indexed, and you get a duplicate of every page carrying an unstyled diagnostic overlay.
Turn it on when you need it, then turn it off. If you keep it on for a longer piece of template work, block the parameter in robots.txt for the duration:
Disallow: /*?tp=1When the outlines do not appear
Two usual causes. Caching, either Joomla's own or a page cache in front of the site, will serve the version without the overlay — clear it and retry. And a template that hard-codes its layout rather than using jdoc:include for a given block has no position there to draw, which is itself the answer to your question.