Free bitcoin online wallet. :
Online wallet where you can store your Bitcoins without having to install any software. They have bin serving this free service for very long time. Using unique login strings and you can activate 2FA for extra security. Hosting blochchain explorer and various API requests.
Everything works fine for many years and more to come. Yet this is not the most secured method of storing Bitcoins. I prefer to spread assets to various exchanges and currencys.
The most secured method:
Is on paper wallet that you have to make your self. Dedicate computer that will not be connected to the internet or any network, printer and bitcoin wallet installed. Since this setup will not be for transactions, you do not have to synchronize this wallet. Now you can print wallet address for payments or print private key for payment tasks. Print it in QR-code format for easy future manipulations.