Hi Rashida,
I am sorry my description was not enough detail, but I am pleased you are willing to investigate.
I have arranged to make the website visitble to you, please refer to hidden content for the URL.
This website is incomplete and is going through a process to replace JoomlaShine template and components with Joomshaper.
The template used is Floox, which displays the page content from an article (not using PageBuilder). Note the first line "SAVE ECHILLS WOOD RAILWAY – EMERGENCY FUND" of the content has a faint box to the left. This box is defined by the following section of the page:
<!--//.entry-header-wrap -->
<div class='col-sm-3">
<div class="author-info">
</div>
</div>
If I interactively remove 'col-sm-3' from the page source using Firefox web developer tools, the indent disappears! What element of the layout sets the 'col-sm-3' CSS class? It is not shown in the template layout editor for the main body (which is the component area) row, or the single column within.
I also tried another Joomshaper template 'Spectrum', which does not have the indent behaviour. I can swap top that template when you ask, to demonstrate if needed.