WHAT IS THE MARK OF THE BEAST?

What is the mark of the beast? And what does it do? And WHERE does the mark of the beast come from?? Pharmakeia——— Pharmacy

“and the light of a candle shall shine no more at all in thee; and the voice of the bridegroom and of the bride shall be heard no more at all in thee: for thy merchants were the great men of the earth; for by thy sorceries (Pharmakeia) (Pharmacy) were all nations deceived.”
‭‭Revelation‬ ‭18:23‬ ‭KJV‬‬

Google——— Strong Concordance 5331 Sorcery=Pharmakeia