The F major scale starts and ends on the note F. To maintain the correct pattern of tones and semitones, it contains a B flat (Bb) note instead of a B note.
As you will have noticed with the scales of G major and F major, major scales starting on different notes are simply higher or lower versions of the same sequence of sounds. This is because they always use the same pattern of tones and semitones. Using degrees instead of note names, any major scale can be written:
The semitones are always found between the 3rd and 4th, and 7th and 8th degrees of the scale. All the other notes are a tone apart. By simply following this pattern of tones and semitones, it is possible to construct a major scale starting on any note. The scale will be named by the note it starts on.