In musical notation, the placement of the stems on the notes follows a general rule:

• Notes written above the third line in the staff usually have downward stems.
• Notes written below the third line in the staff usually have upward stems.
• Notes on the third line in the staff can have either downward or upward stems.

However, this rule is flexible when combining two or more quaver notes that are far apart from each other.

Quavers on the stave

Stems of single quavers follow same rules as crotchets and minims.

But the tails or flags of single quavers are always on the right.