Can I share/transfer an HMI screen with my other Sinolta project?

Yes. Open the HMI Builder and go to the source project. Use Export from the “File” menu option to export the HMI files.
Now close the source project and open the destination project. From the destination project, import the exported file.
Alternatively, you can import directly from your source project by pointing to the source project. This option works if both he source and destination projects are on the same computer.