There are sevarl options out there,
but the best are Joomla! and WordPress as they are free and there are a lot of extensions and plugins for creating an outstanding eLearning website.
Let's take Joomla! for example,
the benefits are:
1) the cms is free
2) there are more tahn 8000 extensions to extend the functionality of the website
3)there is a well-known LMS for Joomla called JoomlaLMS (www.joomlalms.com)
4)the cms is open-sourced that means flexibility
5) cms is constantly updated
6) there are a number of e-commerce tools integrated allowing you not only to manage elearning content but make an additional profit by selling your courses online
Take a look at bpm’online CRM solutions (https://www.bpmonline.com/crm-products), each of which has an online library that stores articles, scripts, guidelines for new employees, document templates, presentations, answers to frequently asked questions, and any other useful materials. The knowledge base takes on features of social networks — users can like posts and share ideas and comments. This helps other users to quickly and easily find the most popular presentation or the most useful answer.
Bpm’online is well-known on the market for merging CRM with BPM and I would recommend everyone looking for a custom solution to their business needs to check the system out. You can try it free with no credit card involved - https://www.bpmonline.com/demo/bpmonline