The most well-known form of crypto funding is the Initial Coin Offering (ICO). This is where a new project can raise funds by selling their own cryptocurrency tokens.
Each token is essentially the blockchain equivalent of a share in a stock that's open to the general public – so you could make the comparison that an ICO is a variation on the Initial Public Offering (IPO).
Crypto projects can also raise funds through a Security Token Offering (STO), Initial Exchange Offering (IEO) or Initial Dex Offering (IDO).
An STO is only slightly different from ICO. A security token represents an investment contract into an underlying investment asset, for example stocks, bonds, funds and real estate investment trusts (REIT). A security token has a lot of advantages since financial regulators consider them securities. The high level of security makes it highly popular among long-term investors.
An Initial Exchange Offering (IEO) is an alternative to ICOs in which a project's tokens are sold directly through a cryptocurrency exchange. Unlike an ICO, IEOs are not open to the general public and any users who want to buy the project's tokens must do so through the exchange's accounts.
An Initial Decentralised Offering (IDO) is very similar to an IEO, except that it occurs on a decentralised exchange.