In the field below "Installed Packages" type: "Tree View". This package has a few settings you can toggle, "Hide Ignored Names" is what you're looking for.
You can configure Atom to ignore specific files by customizing the "Ignored Names" list Atom > Preferences > Settings > Core Settings > Ignored Names. Just add any file or directory to the list.
Important: to activate the Ignored Names list setting, so Atom ignores the files you configured, ensure that Hide Ignored Names is enabled under menu Atom > Preferences > Settings > Tree View > Hide Ignored Names.
There are many ways to customize atom. Check out the official Customizing Atom Page.
From the menu bar go to Edit > Preferences > Packages type in the filter "tree-view" click on the "Settings" button of this package and then check the "Hide Ignored Names" choice.
Now go to Edit > Preferences > Core . In the Ignored Names box enter .* this will hide all the files/folders which are usually hidden in other file explorers.
If you want to hide normal files/folders just add them to this box separated by a Comma , for example : .*, Videos, Music
As stated above, Application menu > Preferences… > select Packages in the sidebar, search for "Tree View", click the Settings button > check Hide Ignored Names.