Aside from the stop/prohibited shape in Office, there are other options for entering the common sign symbol in Word, Excel, PowerPoint or Outlook. Use Icons in Microsoft 365/Office 2019 or Emoji symbols from the Unicode list.
See Make a ‘Stop’ circle / diagonal symbol in Word, Excel & PowerPoint for a better and more flexible option.
The icons in Microsoft 365 have some ‘Stop’ circle with line options like these.
Office 2019 only has two matching icons (the right-most two in the above sample).
Search for ‘Stop’ in the Icons dialog to find them.
Icons are SVG graphics which gives some flexibility. They can be resized or flipped to reposition the line. See Edit options for SVG Icons in Office 365/2019 for more.
Not quite (officially) right
If you’re interested in accuracy to the ISO 3864-1 standard, the Office icon Stop symbol has the same defect as the Shape ‘Not Allowed’ graphic. Both have the same or similar line thickness for the circle and diagonal line. The diagonal line should be 20% thinner than the circle.
Emoji / Symbols
There are various emoji that are like the Stop or Prohibited sign.
There’s also ‘ready made’ symbols for No Smoking, No Littering etc. See 8 simple ‘Prohibited’ symbols for smoking, phones, kids and more in Word
Prohibited emoji is Unicode 1F6AB (see The Old Alt + X trick) like all emoji, the exact look depends on the device or font.
In Windows 10, the Emoji panel shows a non-standard Prohibited emoji with a black border. Find it from Win + . (period/fullstop) for the Emoji panel then search for ‘stop’ or ‘prohibited.
Segoe UI Symbol is the default emoji font in Microsoft Office. Its version of Prohibited is the wrong way around with the diagonal from top-right! See the sample image above.
Windows 10 Segoe UI Emoji
Segoe UI Emoji is the other emoji font supplied with Windows 10. This version of the Prohibited symbol is the correct way around!
Apple, iPad, iPhone
The Prohibited emoji for iOS has a three-dimensional look, accessed from the Emoji virtual keyboard.
Unicode has two symbols that are similar to the Stop shape.
⦸ Circled Reverse Solidus U+29B8
⊘ Circled Division Slash U+2298
They look a little different depending on the font used. Cambria Math or Segoe UI Symbol.
Make a ‘Stop’ circle / diagonal symbol in Word, Excel & PowerPoint
Customized Don’t / Not Allowed symbols for Word, Excel and PowerPoint
8 simple ‘Prohibited’ symbols for smoking, phones, kids and more in Word