How to enable custom script for SharePoint Online (Office 365)

I would like to share my experience with my recent customer in office 365, we manage to register them company in Office 365, but for some reason, after we create new site collection we are not able to add new content editor,  adding custom script and another big problem, we are not allowed to modify the master page in SharePoint Designer 2013, I was confused about all of this problem .
So I started to do some research on google and finally found the solution;

1.  First of all, you need to have proper permission to Office 365 Admin Portal.
2. Click on App-luncher, then choose ADMIN
   
   In case you are not able to see ADMIN icon please follow this link ->”https://portal.office.com/adminportal”
3. Then, choose “SharePoint” from left navigation bar,
   
4. Then, you need to choose the “setting”
   
5. Then, you need to look for “Custom Script” and change to change to “Allow users to run custom script on personal sites” and “Allow users to run custom script on self-service created sites”.
   
   
6. Then, click “OK”. It takes about 24 hours for the changes to take effect.

In Summary, we manage to enable “Customer Script” in office 365.