simply put
The maximum number of Bitcoins that can be mined is 21 million, and the final Bitcoin will be minted around 2140.
Once the circulation reaches its maximum value, Bitcoin miners will no longer receive block rewards.
Assuming no major changes occur to the Bitcoin protocol between now and then, they will be rewarded with transaction fees.
There will only ever be 21 million Bitcoins. That's it. Once they're all mined (which should happen around 2140), no new Bitcoins will enter circulation.
The Bitcoin blockchain is designed around the principle of controlled supply, meaning that only a fixed number of newly minted Bitcoins can be mined each year until a total of 21 million Bitcoins have been minted.