Office web products at different providers

Microsoft Office 365

https://www.microsoft.com/en-us/microsoft-365/

Google Docs

https://docs.google.com/
https://sheets.google.com/
https://forms.google.com/
https://docs.google.com/videos/
https://docs.google.com/presentation/
https://drive.google.com/

Office Docs for Chrome  

https://www.offidocs.com/

Opendesk

https://www.opendesk.eu/

Nextcloud Office

https://nextcloud.com/office/