How to activate database log in dynamics 365?

Dynamics 365 similar to AX 2012 in this feature,
you can trace changes for the existing record and also you can track the new transaction.

To activate database log in Dynamics 365 :

Go to system administration/setup /database log setup.

just click new to run the wizard and click next

The wizard group tables as you see below
you will see the main table only if you need to see all tables, just click show all tables

you can select all fields in a table or select specific fields as below and click next

you can track transaction (new/update /delete /rename primary key) and click next

you will see the summary for your setup and existing activated log

 click finish to finalize this setup Go to system administration/inquires/database log. to trace changes for your record

you can find the type of log and creator,..etc

1. Table:  This filed contains the integer value for each table. A unique integer number attached to each table in Dynamics 365.
2.     Creation Date: This contains the date and time on which entry in sysDatabaseLog is created.
3. Data:  X++ container type this contains the data.
4. LoggType: This described insert, update or delete operation is performed at the result current entry is done in sysDatabaselog. It is of the enum type. DatabaseLogType::Insert

to see changes for the select record click history tab 
also you can clean this log by click clean log button 

but take care of database log functionality, it will record all changes but database size will be largely based on your database activation 

also, you must clean this log periodically