Most websites that are programmed today are done so with a content management system attached to it. This CMS system may be a bespoke one which has been made by that programmer or the web company or It may be an off the shelf one such as WordPress or Drupal. A CMS system is there to allow people to make changes to the website with easy and without having to go in to the code all the time. Often web developers will give their clients access to a content management system to allow them to add / edit or remove certain pages or products on the site. Some developers will still do the changes for their client but will do so through the CMS instead or though code.
When giving CMS access to a client it is important that you give them the right level of access. You may be tempted to just set them up as an Admin so you can be sure they have access to everything they need to but this may mean they can make changes that will have serious implications on the site (if they don’t do them correctly).
Always give a client the minimum level of access needed for them to complete the tasks they may need to. You may even decide to hide all other areas of the CMS system to keep the process simple for them to navigate through.