Hello Aniket
PVST+ is the default configuration on most modern Cisco switches. If you have changed this default and you want to revert back to PVST+ you can do this by issuing the following command: spanning-tree mode pvst.
Now the fact that the ‘+’ is not included can be a bit confusing. Keep in mind that plain PVST is no longer configurable on a switch, it’s always PVST+ so even if you see ‘pvst’ alone in the command, it is always PVST+ that is being referred to.
The advantage of PVST+ is that it sends 802.1D compatible BPDUs, as well as Cisco proprietary, making it compatible with non-Cisco STP implementations.
The spanning-tree mode command can be used to change the type of spanning tree that is running. Depending on the IOS version, it could be MST, PVST+ or Rapid PVST+ to name a few. More about this command can be found here:
I hope this has been helpful!
Laz