How to use fire Arrows

[Jay]

How do I ignite fire arrows? I read a post saying it was 'T' or 'H' however neither of those seem to work

[Maester Rawl]

You can only use that command in sieges.

[H3YimDR3W]

You also need particle systems activated in Graphics or else they will look like regular arrows. Same for "a certain companions" sword.