What is 1 lot on the trading platform?

Lot size varies depending on the instrument being traded.

Typical definitions include:

Forex – 1 lot equals 100,000 units of the base currency
Indices – 1 lot equals 1 contract
Cryptocurrencies – 1 lot equals 1 coin
Gold – 1 lot equals 100 ounces
Silver – 1 lot equals 5,000 ounces
Oil – 1 lot equals 100 barrels

Some instruments may have different specifications depending on the platform.