The method of incentivising resource-consuming activities to reach a network consensus is called Proof-Of-Work.
Here's a recap of the process: from initiating a transaction to getting it mined on the blockchain.
Miners have to resolve a mathematical problem before getting rewarded by the network.
If it takes more resources to solve a problem than to verify it, the system can be a Proof-of-Work economic measure.
Because the number of miners plugged on the Bitcoin network varies, the mining difficulty adjusts itself to the network.
Every 2016 blocks, the mining difficulty changes so that the previous 2016 blocks mined would be mined in exactly two weeks from then.
On average, 2016 blocks in two weeks represents one block every 10 minutes.
The Bitcoin network automatically adjusts its difficulty in order to keep mining one block every 10 minutes.
Miners are capitalists, they work on the Bitcoin network because they are rewarded to do so, earn profit out it. The act of mining is resource-consuming and it involves both fixed and variables costs.
Miners could allocate their time, equipment and energy to other tasks, therefore, the network rewards miners in such a way that they are incentivised to continue working of the network. Miners seek profits and earn their income through two sources:
In order to issue a transaction, Bitcoin users incur a small fee, transaction fees, that are disbursed to miners.
On the other hand, when a new block is generated, new bitcoins are mined and rewarded to the best performing miners. The network has not reached its maximum supply just yet, when a new block is generated, new bitcoins are mined. These freshly created coins are rewarded to the miners that secured the specific block.