Which templates? It is possible, everything is in the CSS of the theme. Change elements there.
Rodolfo Hernandez
Arvixe/Elgg Community Liaison
I am running the basic light fro elgg 1.8.
Usually the way you customize the HTML is by building your own theme or installing a theme that makes the customizations you want. I'm not personally aware of a plugin that has a WYSIWYG editor for the layout, etc.
First thing you need to do is to find what view (page) you want to modify. It is useful to activate an option that shows path of views as comments in code. You need to active plugin "Elgg developer tools" and activate option "wrap views" (or something like that).
Now you can see in html code path of view you want to modify, you have to write a plugin and overwrite that view.
Create a plugin: http://docs.elgg.org/wiki/Plugin_development
Views functions: http://docs.elgg.org/wiki/Engine/Views
Id suggest you to download some plugin theme available and get your hands dirty with it rather than messing up the core.
my 2 cents.
Most of the css is actually found within php files, and is compiled using the elgg views system. I've created a plugin tutorial specifically for people starting out.
Take a look: http://community.elgg.org/plugins/839775/1.8.3/customize-css
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