I am newcomer and very interested about bitcoin. I need a wallet before I am purchase some bitcoin. What is the best and most secure bitcoin wallet?
Your suggestion is very important to me
https://bitcoin.org/en/choose-your-walletthere is nobody that can give you a complete answer to this question... Can you tell us what you plan on doing? Purchasing a large amount of BTC as an investment, experimenting, buying from online retailers, buying in physical shops, trading altcoins...
Each of these usecases will result in other recommandations... And even then, the recommandations you'll get will most probably be personal opinions rather than hard facts.
The only no-brainer i can give you without knowing the usecase is: don't use web wallets or exchanges for storing BTC, unless it's for keeping a very minimal amount of "spending money" when you're on the road... Or in case of an exchange: don't keep your BTC on an exchange longer that the time you need to deposit, exchange and withdraw your BTC (don't even leave it on an exchange overnight).