Pinning files and folders is a new feature in all the Office programs that allows you to pin favorite files and folders so you can QUICKLY and EASILY access them. Each app has it's own pins. For example, you can pin spreadsheets in Excel and presentations in PowerPoint. You can also pin folders you frequently use to save to or open from.
Let me lay the groundwork with a personal example. I use Excel many times a day and sometimes upwards of 15-20 files over a couple of days. This means a file that I opened just 3 days ago is no longer in my "recent" files. This is where PINNING a file comes into play. I have financial files I use every couple of weeks in Excel that I PIN to the top of my recent files so I don't have to browse out to find the drive and click through all the sub-folders it is stored in. I save myself a TON of clicks each day by doing this for my "frequent flier" files.
I'm currently working on a writing project in Word. I don't work on it every day but I do work on it about once a week or so. Like in Excel, over the course of a week, I've opened or worked on quite a few files. Maybe my writing project hasn't fallen off my "Recent Files" list but it's for sure fallen towards the bottom of the list. PINNING this file to the top of my list of Word docs allows me to find it quickly when I'm ready to work on it. (It also reminds me to work on it because I see it every time I'm opening a file in Word).
One more. I'm working on a project where I'm saving a lot of presentations. There are originals and versions of originals, a lot of different PowerPoints. By PINNING this folder to the top of my recent folders list, I'm able to quickly save to it and open from it with out having to click - click - click to find the folder.
I'm going to show you screenshots in PowerPoint but these steps will work in all the Office Apps, Word, Excel, PowerPoint.
You can pin a file to your Task Bar for even EASIER access to a file. This means you don't even have to open the app, just right click on the app on the Task Bar and pick the Pinned file.