Hi,
The service manual does mention support for M2 SATA3 SSD support. You will first need to check if the actual slot on the motherboard is present as sometimes in models that did not come with M2 SSD the physical slot is missing
On page 29 of service manual you can see the steps to remove the bottom cover
http://h10032.www1.hp.com/ctg/Manual/c05228250

So if the slot is there you can install an M2 SATA3 SSD such as the Samsung 860 Evo or similar of your desired capacity. If the slot is not there you can replace the 2.5" HDD with a 2.5" SATA 3 SSD such as the Crucial MX500 or similar of your desired capacity.
Hope it helps,
David
Please click on thumbs up for thanks
Please click on accept as solution if answered your question