As per Company guidelines, Arial size 10 should be the default font used in our business applications.
Unfortunately this cannot always be set as default centrally, so to check or change it back to the Company default here's what you do:
To set these as default in Outlook;
Click File

Then Options

Then select Mail, and 'Stationery and Fonts'

Here you’ll find three font types for:
- New mail messages
- Replying or Forwarding messages
- Composing and reading text messages

Click on each font setting and select Arial as font, Regular, as style, 10 as size of text
To set these as default in Word;
On a blank Word document:
- Click on the Home tab on the top menu ribbons
- In the Font section, click on the window expansion icon

- Set up the Font, style and size to match Arial Regular 10
- Click on Set as Default, and select for 'All documents based on the Normal.dotm template' and click OK

To set these as default in Excel
Click File
Then Options

On the General tab, under 'When creating new workbooks' section change the default font and size accordingly. Then click OK.

Powerpoint - unfortunately does not have the option for setting default font at this time.