I wanted to know that, can I restore backup of SQL Server 2016 Standard edition database into SQL Server 2016 Express edition database.
Or vice-versa
Sometimes:
Yes you can. Right click on your databases in SSMS (Task -> Back up) and create a back-up of your database, move it to the other host and restore it by right clicking on the server name in SSMS and chosing Restore.
Note that some functionality does not work in an Express edition (e.g. SSIS and SQL Agent).
I believe that is definitely doable, however, Express edition can only hold databases 10 GB or smaller, so make sure that when restoring from any licensed version to Express edition , the database is under that size threshold. I can't think of any gotchas restoring from a Express to a licensed edition.