Shared PDFs
Most RPGs have a fillable PDF version of the character sheet. All you have to do to make that character sheet visible to your group is put it on an online PDF-sharing application, such as:
Google Sheets
Hobbiests have made character sheets using Google Sheets for various RPGs, which is a great idea because they can implement auto-calculation and can be easily shared and collaborated on.
The oldest way to share character sheets on the internet, Mythweavers has character sheets for just about any RPG.
CSO is a new simple website for creating sheets with modularity for any system, and then sharing it with your players. From their roadmap it looks like they’re trying to build it into a full VTT too.
D&D Beyond
See the section on DnDBeyond.