Spam is any kind of unwanted, unsolicited communication. For these types of suspicious emails, be sure NOT to open any links or attachments.
To Report as Spam
Access your Gmail, open the email you want to report as spam, and click on the Report spam icon.
If you have more than one email message to report, you can also click the checkbox next to each email you want to report and then click the Report spam icon at the top.
Google will then receive a copy of this reporting for analysis to help improve their spam filters and the message will be moved from your inbox into your Spam folder.
If you accidentally marked a legitimate email as spam, you can find it in the Spam folder and click Not spam to prevent future messages from that sender from going to spam.
Additional information: What to Know About Spam and Phishing Emails