To see which disk is available for swap disk use.

lsblk
blkid
df -Th

Format the disk.

fdisk /dev/xvda

Create a swap disk.

sudo mkswap -f /dev/xvda
sudo swapon -s /dev/xvda
# or
sudo swapon /dev/xvda

Check if swap disk is available.

lsblk
free -h 
cat /proc/swaps
cat /proc/meminfo
swapon -s
top
vmstat
vmstat 1 5