I know that this is gonna be a pretty generic question. I finally started refining my knowledge about arrangement, and I was wondering: are there any conventions about arranging strings inside a pop song? For example During a chord progression being played by piano for example, should I build a string progression made by the 4th, 5th, 7th of each chord? I started studying more deeply subjects like arrangement and orchestration and I would love to understand more. I also know that many rules are subjective and in many cases it's all about taste.
Thank you in advance and sorry for my ignorance