I wrote with a ballpoint pen for many years. My favourite is the Uniball Eye fine (=0.7mm) permanent and waterproof. My favourite colour is
wine red - dark and highly visible for marking up engineering drawings.
A warning though do not take it on plane - the change in air pressure causes the ink to leak out. If the cap is on it will fill with ink - permanent and waterproof.
In grade 8, the Canadian teacher did not understand that biro was the Australian term for a pen, after the inventor.
In order to reduce my use of plastic, I am saving my remaining pens for special use. For everyday use I am converting back to pencil.
When I started school, the teacher said that my work was far too grubby and that I needed to change from HB pencils to 4H pencils. I used Copperplate 4H for the rest of my school days.
Now because I like a thick dark line I am using 4B, and 6B pencils.