First and foremost, you should have a Google Search Console account, log into your account and open this "Fetch as Google" page. You can add your desired website articles here. I added a sample article and clicked on "Fetch" button. If your status is "Complete", you'll find an option called "Request Indexing" next to that, click it!
This is the final page, you can verify the article URL once again and click on "Go". You can select "Crawl only this URL" itself for now. Google won't take the action asap, but it'll definitely verify the URL you submitted and do the needful.
Single URL. This option recrawls only the URL above. You have 500 submissions remaining of your 500 monthly quota for this choice.
Multiple URLs. This option recrawls the URL above and its directly-linked pages. You have 10 submissions remaining of your 10 monthly quota for this choice.
That's all you have to do for recrawling your articles or indexing them properly. Do let us know if you face any issues or if you have any questions.
MOST USEFUL: Want to find when your blog posts are getting indexed?