There are a number of beats in each note. It depends upon the appearance of the note on the page. The quarter note is a typical note in which there is a circle that is filled in and then a straight line that comes out of the circle on the right of left side. When you see this on a musical sheet, that note must be played with one beat.
This is because quarter notes only have one beat. Typically quarter notes usually have a stem that is drawn upwards and not downwards. However, it can be drawn downwards. Similar to this is the quarter rest which is the pause and it has the same beats as the quarter note.