Refer below link.

[Solved] Copy data from a table of a database to a table of another database in SQL Server

Hi,

Will you please let me know what exactly you want to do with trigger.

If you want to take automatically backup i.e. copy data from one table to another there is no need to use trigger.

You can schedule for auto backup database.

How to set auto backup in Sql Server 2012 Express edition database