Update On 16th Aug 2018
You can create the One year Free Trail using the new link Join the Office 365 developer program today
All the Step are documented by the MSDN on the link
Note: The below mentioned trail program was expired
Microsoft has designed the MS Office 365 Developer Program for the developers who build Office 365 solutions.
The Microsoft Office 365 Developer Program can be accessed through Office 365 Developer Program
The Program benefits are as follow
Click on the Join Now link after accessing the above link Office 365 Developer Program
Fill the Form as show below
After Successful registration for the Office 365 Developer Program , we will get the email with the redeem link.
NOTE: Please be sure you are In-Private browsing to redeem the code.
Click on the Redeem links and complete the Registration Form for Office 365 Subscription .
After successful registration for the Office 365 , we will get with the details of your tenant (username , domain etc..) and validity as shown below.