Each blockchain project has its own economy that is based on the blockchain’s underlying token. Depending on their respective designs, projects can have a smaller or larger number of tokens, some of which may be locked or to be issued at a later time.
The number of tokens that are issued and not locked is called “circulating supply”. The circulating supply + the locked tokens are the total supply. The total number of tokens that can exist is called a maximum supply. Bitcoin and Elrond have a maximum supply and are therefore scarce, while other projects do not and continuously release tokens into circulation via an issuance mechanism.