The taxes you have to pay for your Bitcoin or other cryptocurrency differs from Country to country.
The norm in EU is that there are no Taxes on Bitcoin yet, but countries like "Norway" re-visited the Bitcoin tax statement and made their own bitcoin tax.
So in Norway you will have to tax your gains on Bitcoin like any other currency. (20-30% of your gains)
Every year you will have to deliver a yearly report of how much you value you own to the state and how much you have traded.
If they ask for it you will also have to deliver a transaction history that matches this value.
In other countries like Netherlands you have no Tax on bitcoin, yet. I believe we will all pay taxes on Crypto in the future. The point of crypto is not to dodge tax, but to get faster, cheaper, private and a economy free of government influence.
How a country is going to tax cryptocurrency when you no longer will have to turn it into fiat is still uncertain, but my grandfather told me that there are 2 certanties in life. Death and Tax.

(Hope this helps)