Existing Partition Table

[root@server ~]# fdisk -l
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 41861119 20417536 8e Linux LVM

Example: I want to add /dev/sda3

#fdisk /dev/sda
Command (m for help): m
Command (m for help): n
Command (m for help): t
Command (m for help): 8e
Command (m for help): w

#reboot

Create Physical Volume
pvcreate /dev/sda3

Extend existing Volume Group

[root@server ~]# vgs
VG #PV #LV #SN Attr VSize VFree
rhel 1 2 0 wz–n- <19.47g 0

for the vgs output we will extend rhel volume group
#vgextend rhel /dev/sda3

Extend existing Logical Volume

#lvextend /dev/rhel/root /dev/sda3

In this example I will expand the mount points for root partition
[root@server ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 12M 16G 1% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/mapper/rhel-root 18G 3.3G 15G 19% /
/dev/sda1 497M 172M 325M 35% /boot
tmpfs 3.2G 0 3.2G 0% /run/user/0

#xfs_growfs /dev/mapper/rhel-root

#reboot