PPM Accordion is the new WordPress plugin that allows you to insert expand collapse accordions in just one click by using its TinyMCE button present in WordPress visual editor on add new & edit content pages.
Installation & Usage: Install and activate PPM Accordion. Upon activation the plugin automatically adds a TinyMCE button in visual editor.
How To Insert Accordion In WordPress Post ?
Visit your admin area Dashboard -> Posts -> Add New page and click 
button:
[ppmaccordion][ppmtoggle title="Title"]...[/ppmtoggle] [ppmtoggle title="Title"]...[/ppmtoggle] [ppmtoggle title="Title"]...[/ppmtoggle][/ppmaccordion]
This plugin will add the above block of shortcodes. Now simply replace ‘Title’ with Accordion Title and (….) with collapseable content. See it live working here.