They can be similar depending on the type of business activity. Office expenses are expenses related to maintaining an active office such as pens, paper, post stamps, ink toner, etc. Supplies expenses are expenses more closely related to the actual production of a product but aren't directly related to the cost of goods sold - think something like a box of nails or screws that you may use over the course of a year or a gallon of paint.
In the end, all of these expenses get totaled together, so if you aren't entirely sure where to put some items the more important thing is that you don't double count them. The distinction is there to help keep your records accurate in case you ever need to prove your expenses.
