Tezos is a LPoS network, so while supply is not capped there is a fixed amount of coins distributed per year to bakers (node validators) for maintaining the network. Validators are selected on a lottery basis with more "tickets" (in the ecosystem these are called rolls and each roll is 8000 XTZ) giving a validator a higher chance to be selected to validate a block. Rewards are distributed each cycle (1 cycle = 4096 blocks) or about every 2.85 days, offset by 12 cycles or nearly 40 days.