Our macOS minimum recommended spec

If you're looking to choose a new Mac for yourself or your team, then assuming you are using it for 'normal' office use, (surfing the internet, using Microsoft Office applications, email and so on) any current Mac is more than up to the job as Apple do not sell Mac's with a lower spec than our recommended minimum. 

Operating System	MacOS 10.15.6
CPU	Any of the Apple M series processors If you're buying a Mac with Intel chips, then i5 or better and you won't be disappointed. Until you try a Mac with the Apple M processor.
RAM	8GB RAM or more
Storage	250GB SSD or more.
Display	With the Apple Retina Display, any new Mac comes with a great display.
Graphics	This shouldn't be a consideration if you are buying for normal office use. If you have specific requirements around driving the Apple XDR display or multiple 4K (or higher) monitors, then you will need to look carefully at the Graphics Capabilities of the Mac.

Reasons to buy a Mac

1. If you are considering computer performance, battery life and cost, then Mac's with Apple M series processors are the best value notebooks on the market., period. They perform incredibly well and currently (Jan 2021) are only beaten in absolute power (but win in price/performance) by high end desktop PC's. 
2. They're built to last - construction is incredibly good and it's not uncommon for them to last 4 years or more.

Some downsides

1. You may not be able to run the software you want on them.
2. To get them as small as they are, MacBooks have RAM soldered to the main board and disks are non-standard, meaning that whether you buy a Macbook Air, Macbook Pro or Macbook, you need to make sure you are choosing something that has the capacity to cope as your needs change longer term. 
3. iMac's, the Mac mini are difficult to upgrade and less and less is able to be upgraded as new model's are announced. 
4. Mac Pro's are a longer story in terms of upgrading. But you shouldn't be considering one of these for 'normal' office use.