Hi Shannon

Thanks for posting your question! If you double click a cell (as if you're going to add text) then select the Line Color icon you can change the border of that single cell.

Let me know if you have anymore questions!

Hi Ashley thank you. But can I select only one side of the cell? Or does the border need to be all 4 sides the same? I am wanting to format similar to Excel where all 4 sides can be formatted differently. Thanks!

Hi Shannon thanks for following up! There isn't specific functionality to accomplish this so would you mind submitting your idea to our Product Feedback section?

A workaround that might work is setting the cell border color then adjusting the colors of the surrounding cells until just a single border is colored. In the below screenshot I first made the cell border red then when in with a dark black color to illustrate what I mean.

I realize this isn't a perfect solution but I hope it helps.