Safest is to make paper wallet with offline computer. You should search for that on this forum or on goggle. It also depend what coin you plan to store. Some if is some new tech you might have more problems if is just a btc clone or a token is simple.

So so safe but super simple is buying Ledger S hardware wallet.  You can get it for like $70 and can store quite a variety of coins now, soon even Monero.