The most reliable is an offline crypto wallet. In this case, you can install the wallet on any computer even without access to the Internet. Ledger and Trezor hardware wallets have a high level of reliability. 

A digital wallet is a software program, online service, or electronic device that stores users’ payment data and processes payments. More here https://sdk.finance/digital-wallet-guide/

Do you want to promote your cryptocurrency project and gather new target audience? Then you need an advertising network that will give you the opportunity to publish ads for your cryptocurrency project. Follow this https://bitmedia.io/become-a-publisher link to the website and you will learn how to advertise your cryptocurrency project and reach your target audience. This company is ideal for meeting the needs of a wide range of cryptocurrency projects. Because this is where you can tailor your advertising services to your project's requirements.