The electrical project file has a .WDP , which is essentially a text file (can be edited with notepad) and when we create project in AutoCAD Electrical then two more file will be create .WDL, AEPX, WDT.
We can have as many projects open in Project Manager as you wish, but only one project can be active at a time. Project-wide functions process drawings from the active project.
Right Click in any project and make active project.

If the project manager disappear, so we need to go Project in Menu bar and click on Manager. 

  • Project File

Create New Project

Project Manager > New Project > Give The Project name (exp. Test) and Give the path > Ok 

The project file (.WDP) is created in the specified folder, containing the project descriptions . The new project becomes the active project. We can now add drawings to the project.
The electrical project file has a .WDP, .WDT, .WDL, .AEPX, .DWG extension, which is essentially a text file (can be edited with notepad) that contains all settings around your project setup.

.WDP with the help of this file we can open the project in electrical AutoCAD.
.WDL With the help of this file, we can assign attributes to the electrical template.
.DWG  this is working file where we can draw the object 
.AEPX with the help of this file we can see the path of project 

After Creating project we need to add the .DWG or drawing file in project, There are two types of adding .DWG or Drawing file to the project
Add New DWG or Drawing file
Add Existing DWG or Drawing file

Add New DWG or Drawing file In Project

Project Manager > Right Click in Project > Select New  > Drawing Name > Select The Template > Ok 

Add Existing DWG or Drawing file In Project

Project Manager > Right Click in Project > Select New  > Drawing Name > Select The Template > Ok

Copy Project In AutoCAD Electrical

There are also two types of copy in AutoCAD Electrical.
Copy Active Project 
Copy Existing Project 

Copy Active Project

  Menu Bar > Project > Copy > Copy Active Project > ok > Select New Path and Name For New Project (.WDP)  > Save > Ok > Select Dwg from Existing project > Ok > Edit or find/Replace the Drawing name (.DWG) > ok 

Copy Existing Project

Menu Bar > Project > Copy > Copy Existing Project > Open Project > Select New Path and Name For New Project (.WDP)  > Save > Ok > Select Dwg from Existing project > Ok > Edit or find/Replace the Drawing name (.DWG) > ok