Use atom as text editor

Hello, recently Ive been using atom to take my notes for my lectures. I was wondering, if there’s a package or a way to bold certain line within the text-editor, change the color of certain word etc.

I would use markdown for your notes.
Install package markdown-preview-enhanced to preview and publish your notes. Use pandoc with yaml frontmatter in your notes to create slide presentations, html, pdf, images.
Explore also Rmarkdown.