I have several options.
If you are security conscious there is End-to-End encryption with ProtonMail, or if you require an affordable option for many users you can opt for standard email.
ProtonMail offers end-to-end encryption that is protected by Swiss privacy laws, however it is only accessible through your web browser or with the ProtonMail app unless you install additional software to allow 3rd party access in another email client such as Outlook.
Standard email is more affordable and allows for easier access with your email client of choice.