To convert Photoshop Artboard into a picture ready for use on the web or print, you need to export the artboard.
Step 1
Select one or several artboards on Layers Window

Step 2
Go to File -> Export -> Artboards to file
Step 3
Set the Destination folder where you want to save the files.

Step 4
Enable checkboxes Export selected artboards and Include Background in Export.
Step 5
Select FileType from the drop-down. Configure file type options for fine-tuning the export
Step 6
Press Run button. Photoshop will automatically save the files to the specified folder.
For more read about Export in Photoshop on Adobe help center

