You would need to add some code in order to display Usage Statistics plugin numbers on the article page, s. Abstract views, PDF views and Download Stats Made Public 😶 - #7 by beghelli.
To assign DOIs to your articles, you could use the DOI public identifer plugin (under System Plugins > Public Identifier Plugins). Note that this plugin only assigns the DOIs to the articles in OJS. The DOI registration can then be done either manually or using the Import/Export Plugins DataCite, mEDRA or Crossref, depending on your DOI agency.
Best,
Bozana