@annak1990 Thanks for reaching out and welcome to the Microsoft Edge Insider's community. @Aelisya is correct!
At this time, sync and its related profile services are not yet implemented on Linux. We encourage you to sign in to a local account, however, you will notice that you will be unable to sync your data from other devices. This will also affect the ability to open protected PDFs.
The team is working hard on bringing this to our Linux version of Microsoft Edge. Keep an eye out here for any updates we have about sync and its related services!
Fawkes (they/them) Program Manager & Community Manager - Microsoft Edge