Summary: Makers create buy or sell orders that are not executed immediately but go on the order book. Takers fill the buy or sell orders created by the makers.
Cryptocurrency markets are made up of makers and takers. Every trader turns out to be one of these two categories.
You become a “Maker” when you place an order, for example a limit order, which is not executed immediately because there is no matching buy or sell order on the order book that can fill it. So your order will be added to the order book, waiting to be filled. At this point you have made the market, increasing liquidity of the exchange market which makes other trader’s buy or sell orders more likely to get matched instantly, and are therefore considered a “Maker”.
You become a “Taker” when you place an order that matches an existing order on the order book thereby being able to execute immediately. A taker removes part of the order book, decreasing the exchange market liquidity. If a “Taker” order’s amount is too much to fill completely, the remaining amount will be a new “Maker” order and stays in the order book.
Trades from market orders are always takers, as market orders are always fulfilled before going on the order book.
If you place a limit buy below the current market price, or a limit sells above the current market price, then you will pay the Maker fee when your order is filled because you added liquidity to the order book until others take your offer.
If you buy or sell using a market order, you will pay the taker fee because a market order immediately removes the liquidity of the market.