Add a Parallel Constraint

1. Select Sketch | Constraints | Add parallel constraint.
2. Select the first line. This line keeps its position.
3. Select the second line. This line moves so that it is parallel with the first line.
4. Add more parallel constraints by repeating steps 2 and 3 or finish adding parallel constraints by pressing the ESC key or the middle mouse button.

The Distance constraint between two lines includes the Parallel constraint, in a sense.

If you add a line parallel to another line by pressing the E key, the Parallel constraint is created automatically.

The axes of the sketching coordinate system retain their directions, and an axis can be used as an element when determining the constraint.