How many new bitcoin could miners receive per block at the beginning?

Detailed explanation

At the launch of the Bitcoin network, permitted new issuance was 50 BTC per block. This amount is the block subsidy: the bitcoin that may be newly created under the rules in a valid block.

Transaction fees are separate. They come from existing bitcoin and do not increase the money supply. A reference to a miner's total payout may therefore include both new issuance and fees.

The 50 BTC was the starting value, not a permanent payout. After the scheduled halving interval, permitted new issuance falls. A miner cannot choose to return to the earlier higher amount: rule-following nodes check the allowed amount for each block height.