I found this to work for various versions, up to the latest version of Word. But please note that this will affect ALL Office applications, not only Word! I'm actually copying & adapting from this page on askvg.com . If you don't feel to edit the registry yourself, you can download the necessary automatic script from that link. Otherwise, take the following steps:
Close any office application.
Press "WIN+R" key combination to launch RUN dialog box then type regedit and press Enter. It'll open Registry Editor and go to following key:
For Office 2013: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common
For Office 2016: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common
For Office, 2019 & 365: HKEY_CURRENT_USER\Software\Microsoft\Office\17HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common
Check if there is a key "Graphics" existing. If not, right-click on Common key and select New -> Key option. It'll create a new key, set its name as Graphics
Now in right-side pane, create a new DWORD DisableAnimations and set its value to 1
Close Registry Editor and open any Office application. Changes are instant: no more animations and effects.
If you want to restore default animations, change value of DisableAnimations to 0 or simply delete the DWORD.