Hello!
Tell me which plugin to use to display the articles of the site.
I tried to install Table of Contents Plus and Easy Table of Contents. Table of Contents is not displayed on the site.
https://hhealth.info/blog
Good evening Alexandr
Sorry but not clearly understand 
can you tell me what is your final goal? perhaps you can provide an example?
I want the table of contents (list) of all articles on the site to be displayed in the sidebar.
So that site visitors can see all the articles and find the one you need.
Good morning Alexandr
WordPress already has a built-in widget for recent posts (table of content) and you can use it, if default widgets are not enough or not suits your needs you can search for third-party plugins 
Hello Noda !
I made a page titled “Article Directory” and brought this page to the right sidebar.
So the question is closed …
Great I will close this case now, Feel free to contact us again if you have other questions Thanks!