While revit architecture can create railings automatically you can also do this manually for greater control or less conventional shapes.
Add railing to stairs revit.
Click architecture tab circulation panel railing drop down place on host.
In the type selector select the type of railing to place.
Place a railing on a host.
If you did not include a.
For placement on stairs only.
Select the created railing and from the modify railings tab select pick new host then select the stair flight.
On the position panel click treads or stringer.
You can add free standing railings or railings that are attached to stairs ramps floors and other hosts.
Place a railing during stair or ramp creation.
The railing is now placed on the flight of stairs.
Set up automatic railing placement for stair or ramp creation.
Option 2 in the plan view draw model lines of the required railing path.
These will be displayed in green.