As a manufacturing engineer, I’m mostly in an office when I’m not actively dicking about on the production floor or talking with my production operators. Most of my desk time is

1. Answering questions from people who aren’t me about my manufacturing lines: specifications, output, inputs, could I do experiment XYZ if they sent me info. Subject Matter Expert is the term the company uses. Debatable if it’s accurate, but it’s the expectation.
2. Answering stupid questions for people who could absolutely open an app or walk and look in person but would rather be handed the info.
3. Collaboration with other employees: be it Quality as to what hoops I need to jump through to do something, providing process data relevant to a manufacturing defect they were alerted to, pestering other engineers to see if they’ve done anything like what I’m up to because it’s a good shortcut, or trying to work out how to use a system I’m unfamiliar with.
4. Tracking output metrics: Management loves the same numbers tracked 5 different ways and having them reported to them constantly.
5. Meeting prep: either making a slideshow, crunching data to present, updating a project tracker (see above), or reading all the relevant emails associated with the meeting because earlier I super just skimmed them for anything I was required to do urgently. 7: Tinkering on things at my desk: familiarizing myself with new equipment/parts, testing an idea out of scraps/easily sourced parts before I ask our Tool and Die team to draw up a design for something sturdier/more expensive, or rooting through boxes for things I inherited relevant to that manufacturing line when I was assigned to it.
6. Messaging folks on teams: lunch plans, thoughts on recent events, or even just sending memes, gifs, ASCII middle fingers to people I like. General screwing around.