1>how many ways can open form and repot
2>how can transfer xpo file from one environment to another
Whats is your requirement? When you are in development instance directly point to AOT>Forms>FormName and simply right click to open it. And when you want to open the form from AX frontend[workspace], then first you need to create display menu item for the form and attach it to Menus.
When you export the project/objects from AX you can specify the particular path to save it, now once it is exported, you can simply copy it and paste in another environment to import it.