After taking part in a token sale or buying tokens off of a cryptocurrency exchange, adding your tokens to be viewed in MetaMask is easy - but it's important you have the correct information of how many tokens you hold and the data from the token sale host on how to provide them. Here we'll show you how to do all that.
After The Token Sale
If you received tokens from a token sale that you have participated in, the host or company behind the token sale should have emailed or otherwise messaged to the community the way to "claim" tokens on an ERC20 compatible wallet. Usually these instructions are sent out right away or even before the token sale is complete, but if you don't have that information or don't know how to find it, please see the next section.
Finding Your Tokens On Etherscan
Etherscan.io has good features to help you locate information about the tokens that you hold. From the homepage you can navigate to the menu bar "Token" and click "View Tokens."
This page shows you a full list of the top ERC20 tokens ranked by market cap. If you don't see your token on this page, you can use the search bar to find it.
Once on a token's page (using AdChain's token AdToken (ADT) here for example) the main information relevant to you at this point is "Contract Address" and "Token Decimals." You'll also need to know the token symbol, which can usually be seen in the headline of the webpage between parenthesis.
MetaMask And Your Tokens
View this article regarding sending tokens with MetaMask's Old UI.