There are various ways in which Altcoins or Bitcoins can be obtained; if the coin supports mining, primarily the coins that work on PoW algorithms fall into this category, those coins can be obtained by a mining process. Coins such as Bitcoin, Litecoin, Ether, Bitcoin Cash, Monero, and others support mining. As discussed earlier, there are various exchanges where cryptocurrencies are exchanged, for fiat currency or even other cryptocurrency; this is another widely used method.
Mining is a process by which new blocks are added to the blockchain. Transactions are validated by the mining process by mining nodes and kept in the blocks, then these blocks are added to the blockchain. This is a highly resource-intensive process to ensure the required resources are spent by the miners for the block to be accepted.
Each cryptocurrency has a different mining difficulty, which is defined by the block height, the number of miners mining that cryptocurrency...