Did you read my previous reply to you?
It depends on the region... actually "pluma" would be the feather pen/quill because pluma means feather. Bolígrafo refers to the new pens that didn't have to be submerged in ink or change cartridges (like a Bic pen) meaning a ballpoint pen. A fountain pen is "pluma fuente" and "lapicero" can mean either ballpoint pen, or mechanical pencil depending on the region.
Because this is a sentence without context, either a formal of informal translation is acceptable. Nobody can speak Spanish fluently or understand it fully until they get comfortable with both conjugations. If you have a significant other and friends, practice using the familiar when thinking about them. Perhaps that way you can associate the familiar with showing love/friendship. Doing that changed my way of thinking about the familiar and allowed me to start using it more.
In class, we always used the formal because that is a situation where the formal is required so that teachers and students can show respect for each other. I just needed to reframe the way I think about it. One of the things that I personally like about Spanish is that showing respect and love is built into the language.