I no longer trust passwords (or any data, really) to 3rd party apps after I bought one and the developer just up and quit on it. Worse, there was an issue with the decryption that corrupted some files, so the data was irretrievable. Lesson learned.
So for me I only use encryption supported by the OS itself. You then can have reasonable confidence it will work and will be supported, and if discontinued, a method to move on will be part of the announcement. I don't use Windows, Linux or UNIX for any of my day-to-day tasks, although I do have those OS's available for specific applications I use or may need to, so I can't be much help as far as browsers, mail or other file encryption there.
Rumour has it that Apple has licensed 1password for the next OS release, which is easily the most used password manager on MacOS, but it's not needed, really, as you can encrypt files easily (and have been able to since the 1990's and prior to OSX).
Just set an encrypted disk image to mount and decrypt on login; everything is there when you startup and is encrypted when you shut down or log out manually or automatically if you set a non-activity timer.
Note that this is different than encrypting you entire User Account or the entire Startup Disk itself, which you can also do easily and prevents any loss of data or information should something be stolen or even sold without wiping the drive, but I would suggest a stringent backup routine if you go that route as any serious HDD failure could render it all un-readable. So backup onto another disk if you go that route.
If it's for online use, virtually every browser will save logins and passwords and even credit card details. I don't use it, but many do. It is NOT secure, just convenient.
Apple Mail (and many other mail apps; eg Microsoft Outlook) support S/MIME, which will encrypt and automatically decrypt eMail sent to any other user who also has turned S/MIME on in their mail app. It does not affect messages sent to a user without S/MIME enabled (in other words, the message is sent in plain text and can be read by anyone intercepting it along the way, which is how "standard" eMail works).
To enable S/MIME you first must obtain a Certificate, which you can do for free from a number of Certificate Authorities. It's the same process you would go through if you wanted to set up an internet presence with your own domain. They make money selling them to business users. I recommend comodo dotcom, but there are others. Then it's just a matter of installing the Cert and turning the feature on in the app's preferences.
For robust security, you can employ a removable drive, such as a thumb drive. Many are quite convenient to carry one way or another; store your passwords there or the file your password manager uses and keep it with you. This is similar to how Google employees keep secure although their system also involves a decryption key on the thumb drive. Google recently reported that of their some 65000 employees not one incident of phishing was encountered over the last 12 months. The "something you know, and something you have" doctrine of security is quite effective.
Remember that if you lose or forget the password to unlock any encrypted file, it's gone. Period. So make sure you can remember or retrieve that password, and think about unusual circumstances that you might experience, such as an accident causing memory loss or confusion. Written down under lock and key in an obvious place (so you don't forget where it is) is recommended. Maybe drop a note into the Safety Deposit Box the next time you're at the bank, or in a home safe, etc. I don't recommend "hiding" it in a book or some such, as if you need to find it for health reasons you may not remember where that is.
I don't provide links in posts and it's entirely due to security reasons (yours, not mine). You will have to type out the url in your browser window, which is the safest method to go anywhere on the internet.
1password is available for Windows, Linux, UNIX, MacOS, iOS and Android
Subscription-based pricing or standalone apps (you might have to do some hunting on the website to find standalone apps) and for older versions of those OSs.
comodo dotcom
1password dotcom