When you are adding markups to a drawing in Procore, you will see two different markup layers in the Filter Markup menu: Published and Personal. (Note: See Filter Drawing Markups.)
When you first add markups to a drawing, they will appear on the Personal Layer, meaning it will only be visible to you. Any user can add markups to drawings on their Personal layer, but you will only see personal layer markups that you've made.
However, if you want other users to see your markups, you can publish them.
Simply select a markup and click the Publish button. You must publish each markup individually. (Note: Only 'Standard' and 'Admin' users can publish markups.)
Once a markup is published, it becomes a static part of the Published layer. In the example screenshot below, only the Published layer is visible. Once a markup is published, it cannot be edited. However, it can be deleted from the Published layer. Simply select the markup and click the trash can icon. (Note: Only 'Admin' users can delete markups.)