WHILE SCANNING IT IS SAVED AS .BMP HOW TO CORRECT IT AS JPEG AND SET AS DEFAULT?
Depends on what software you're using to manage your scans.
Go into scanner settings and change the default save to jpeg, or if there is an option to save photographs this should save as a jpeg. As you haven’t provided details of the scanner software that’s the best we can do.
If open the file in Paint afterward, you can save it as a jpeg or a tiff there.
That would likely depend on the software you are using to scan whatever with.