What are hierograms , i am new to the game

They're the charms from the cash shop, Heirograms were their name in another version of Perfect World and many still call them by that here. They will restore your HP (Health) or Mana to full when they get down to a certain level until the charge of the charm runs out. They can do this every ten seconds.

HP charms restore HP at 50% and Mana charms restore Mana at 75%.

So, say you have a Silver Charm, which has 350,000 HP, and your character has 2000 HP, when you get attacked and your HP drops to half, at 1000, your HP will be restored to full, going back up to 2000, and the charm will drop down to having 349,000 HP left.

However, as I said, this only works once every ten seconds, so if the charm is not done refreshing and you get attacked again for more HP than you have, you will not live.

You can buy potions or craft various items with herbs to help replenish your HP/MP, yes. The hieros aren't the only option, and yes they do come from the cash shop (real money). However, people sell hieros they bought with their real money to players for in-game coins, so no, you don't have to pay real cash to get them.

So, they can only be bought from the cash shop? What is their price in RL$? And their in-game price, approximately?

It would help if people stopped using abbreviations for everything ...

"Q: How can i make hierograms?
A: Depends what your talking about. HP/MP hierograms cannot be made. Patk/Matk/Pdef/Mdef can be made by pharmacists using fuel crystals"

What did 'Patk/Matk/Pdef/Mdef" mean?

Ok, thank you