Forms may be used in more than one project. You might want to use a form that you created for one project in a new project.
Each form is separate module, which is saved as separate file with an .frm extension. All information for the form resides in a file, which includes the code procedures and visual interface as well as property settings for controls.
To ad as existing form to a project, use the add Form command on the project menu and select Existing tab. You need to specify the location and name of the form where it can found.
Steps for adding a existing form:
Step 1: Select Add Form from the Project menu.
Step 2: In the Add Form dialog box, select the Existing Tab and locate the folder and select file desired.
Step 3: Click on Ok
This will add that for to your project and it will appear in the project explorer.