The short answer to this question is yes, you will be able to manage your website if you have a CMS however there is a ‘it depends’ element to the answer. Most content management systems will enable you to manage pretty much everything you will need to run your website however, the areas that you can manage (templating, custom styling, modules, widgets, etc) will be determined by two things – the CMS your website is built with and your level of access.
How to find out if your website is running a content management system
If you’ve currently got a website and you’re wondering if it’s actually running a content management system but not sure which one, the easiest way to find out is go to https://whatcms.org and type in your website address and the system will tell you what CMS your website is running. Simple!