Web based office suites that have some level of security:
MSOffice365 and Google Docs have very little expectation of privacy (both companies are known to snoop on your accounts).
There is also ZOHO Workspace (India) which is a reasonable competitior to Google's GSuite. There is also the NextCloud Office, which is a built in version of Colabra or OnlyOffice into their NextCloud server program, which is self hosted.
Offline office suites that don't have telemtry issues or data mining are best for security. LibreOffice is my top choice. Other programs include Corel wordPerfect and SSuiteSoft Office software.
There are others, but these are the best of the bunch.
There are many messenger and video chat apps, but few take security & privacy very seriously.
Minds, Telegram, Signal, Riot.IM, Line, Wire, Jitsi, Viber, Ekiga.
All have their strenghts and weaknesses.
Telegram & Minds don't have video chat.
Riot is probably the most secure and private, but not easy to learn.
Wire is a good commercial grade system for businesses.
Jitsi Meet looks very promissing and easy to use.
EKiga is a great multiplatform Open Source project.
Depending on what your needs are, and who your communicating with, determines which apps will work best for you.
I use Telegram instead of twitter.
I have Minds, Viber and Jitsi meet.
I do not use Facebook Messenger apps for phone (privacy failure)
All email systems should be using HTTS, and therefor be "secure". however, in transmission of email, often messages are translated to plain text and therfor not secure. There are several ways of getting messages to one another securely. Here we will focus on the email programs.
Hushmail, Proton mail, Tutanota.
Muy clients have used Hushmail for years.
Reasonably priced and to administer.
Proton mail has sketchy issues with "certain" gvmt agentcies.
I have a Tutanota, but found it dificult for other users to figure out.
Other mail services, (Gmail) can be secured, but you have to configure the mail suite (basic, pro or ent, not free).
Whichever you choose, know the right procedure to send and receive securely.
Other ways to send / receive files securely via web based apps.
Support tickets, ERP and CMS programs can be great for this.
Run from a private server for added security.
Cyberx Password generator
EPIM for password management, tasks, appointments etc. Can be run from an encrypted flash drive.
Alternate software's Shredder.
(aka Alternate File Shredder)
Eraser (file Shredder)
VeryCrypt, SSE File Encryption for android
Splashtop Business, Anydesk, TeamViewer
for remote desktop management.
7zip for basic file enc with password.