General Overview
The block reward is given to the miner as soon as he has found a new block (calculated its hash value). In addition to the Block Reward, the Bitcoin miner also receives the Transactions fees from transfers.
How earns Block Rewards and how does it work
As stated in the article Blocks chapter “Blocks and Mining” miners are compensated with a block reward for each block found. However, finding or rather mining blocks literally refers to calculating a complicated arithmetic problem in order to validate the correctness of individual bookings (transaction) and the consensus of the network. To do this, the miner must provide computer hardware and power. The perpetual debate about the energy consumption of the Bitcoin network in the media is only worth mentioning.
To motivate a miner to do the work, he is offered a reward in the form of credited Bitcoins.
The number of bitcoins awarded in the form of block rewards are defined in the Bitcoin protocol and is halved after every 210,000 blocks (approximately every 4 years). See also the article Bitcoin Halving. The important question is where is the motivation for the work if the reward is halved every 4 years? This is quite justified but can be answered relatively easily. Bitcoin is limited to the number of 21,000,000. There is no more. Due to the limitation of the supply with increasing demand, the value of the BTC will increase in the long term.
Transaction fee
In addition to the rewards, miners receive the transaction fees that are incurred when transferring BTC. The sender of a BTC can usually determine how high the transfer fee should be. This can quickly give the impression that the sender can determine whether or not a fee should be charged for a transfer. This is true, but there is a catch. Not paying a transfer fee has at best an impact on the transaction speed. This is because miners will prioritize transactions that pay a fee. In the past, wallets had a default transfer fee of 0.0001 BTC, which had to be adjusted individually.
Context to bitcoin halving
Considering that the Bitcoin rewards are getting smaller and smaller due to the Bitcoin halving, the miners need an additional motivation to do the work of mining later on. In 2044, the block rewards would be below 0.1 BTC. The transaction fees can then be the necessary supplement.
Conclusion
The Block Reward rewards miners for their work, but is diminished by Bitcoin halving every 4 years. The expected price increase due to the limitation of the Bitcoin amount and the transaction fees which are additionally paid to the miners should ensure the motivation for mining in the future.