Personally I use KeePassXC on macOS, Windows, and Linux and MiniKeePass on iOS and synch between all devices using iCloud Drive (I would use SpiderOak ONE but t

Personally I use KeePassXC on macOS, Windows, and Linux and MiniKeePass on iOS and synch between all devices using iCloud Drive (I would use SpiderOak ONE but that client doesn't allow uploading files from iOS and I do add entries to KeePass from my iOS device). Keeping an offline backup (or four?) of your KeePass database(s) in various locations isn't a bad idea; encrypting the database backup(s) is also an option if you think you need it. And a printed copy of the KeePass database password in a fire safe and/or safe deposit box could be reasonable fallback recovery method as well. As for the files themselves: Dropbox, iCloud Drive, Google Drive if you don't worry about people at the storage provider being able to reset your password and access your stuff; SpiderOak ONE if you want a zero knowledge cloud storage provider (they aren't the only one, just the only one I've used).