Is it possible to backup sharepoint server backup and restore in on SharePoint online version. Any suitable ways and what can be the compatibility issues if its possible. Thanks!
There are migration tools available, but backup-restore is not the way to think about such migrations.
It is recommended that you base most of your development targeted at SharePoint Online off of Team Site, not even Blank Site.
You can not backup restore to SharePoint Online since you do not have access to the (SQL) databases.
There are some 3th party tools available to migrate content but in my opinion none of those tools does the job really well.
Custom SharePoint (Visual Studio) solutions can not be migrated. Sandbox solutions with .NET code can not be migrated.