When correctly identified as one which can have memory upgraded, see...
•MacBook Pro: How to remove or install memory - Apple Support:
https://support.apple.com/en-us/HT1270
Also note the specs shown may be less in this article than those from
other sources who have tested viability of more than suggested limits
such as OWC macsales, who offers RAM upgrade for the capable MB
/Pro models such the one yours appears to be.
According to specs such as those presented by http://mactracker.ca data
the identify of the model build sales order presents an upgrade opportunity.
For correct identification you could use an Apple Support article and/or lookup by serial number service.
•How to Identify MacBook/Pro models:
https://support.apple.com/en-us/HT201300
•Identify your Mac by serial number lookup:
https://www.powerbookmedic.com/identify-mac-serial.php
•Upgrade Memory of MacBook Pro 2012 & later to 8GB or 16GB 1600MHz DDR3L:
http://eshop.macsales.com/shop/memory/Apple_MacBook_MacBook_Pro/Upgrade/DDR3_160 0MHz_SDRAM
Hopefully your device is identified as one that can see & use 16GB.
Good luck & happy computing! 🙂