No, it is not illegal to write in red pen.
No.
Red
Where you write with a pen.
The Red Pen was created in 1927.
Yes, you can use a blue pen to write a check.
a space pen
Well the ink comes out of the pen and that goes on the paper and if you are not an idiot you can write words.
to write
with a pen
the verb (action) is write
Blue Pen or Black Pen
What do you call a pen with five fingers? Write-handed.