To transfer elements from one development environment to a different development environment, you can use a project package file. Project package files have the .axpp file name extension. A project package contains all the elements from the project. To export a project, select the project to export, right click and select Export Project option. This will open up dialog to enter file name and folder and save to export. 

When you import the .axpp file in another development environment, the elements from the project package file will be imported into the same model that they were exported from. If that model doesn't exist in the installation, it will be created during the import process. To import .axpp file, select menu Dynamics 365 | Import Project..., this open the import dialog where you can locate file, select appropriate settings, select elements and click OK to complete the import. The following screenshot shows the project import dialog in Visual Studio: