Omitting the する after a する verb in formal writing


In reading several Japanese websites detailing how to write a Japanese resume,
I ran across a pattern I found curious. There would be a sentence ending in a
する verb used as a verb (i.e. with particles such as を or に), but without any
following する or even だ or です. I feel like I saw this most in compact job
description bullet points, but it also showed up in longer-form writing
surrounded by です・ます sentences.

Here is an example from one website:

>
> ◯◯大学を卒業後、求人情報サイトを運営する株式会社◯◯に入社。営業職として、新規顧客の開拓を中心に取り組んでおりました。([source](https://employment.en-
> japan.com/tenshoku-daijiten/44323/))

I'd like to use this pattern myself as it feels less repetitive, but it
conflicts with what I've learned, so I'm worried about seeming informal or
inconsistent.

What is this pattern? In what contexts is it appropriate and what connotations
does it have?

