A few questions about the currency and staking

So, I looked through the documentation and read the tutorials, but I still have some questions.
Suppose I want to release my application with my cryptocurrency, I found only information about Keepers and I don’t fully understand whether there is any implementation for issuing pow coins, if not, how can this be done?

The second question is rather general, I do not understand how the interest rate for stacking is calculated, can I guarantee a certain percentage?

I will be glad of any answer, I really want to take part in the construction on cosmos.

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