You can use Mendeley Desktop or Mendeley on the web to annotate your PDFs. Highlight text and add your own notes to the stored copies of articles as you read them.
Your Mendeley account also allows you to access Mendeley Data, where you can share and discover datasets and store your own research datasets in the cloud.
In Mendeley Desktop, use the Tools menu to access your Mendeley Options. You can configure many optional features here:
Your Mendeley account also allows you to upload your CV and get job alerts from Mendeley Careers, a repository of job postings in science, technology, and health.