Here’s a good start:
#popclip
name: Send to MS Word
icon: W
applescript: |
tell application "Microsoft Word"
activate
create new document
insert text "{popclip text}" at end of text object of active document
end tell
(The above block is an extension snippet - select all the text above to install the extension with PopClip)
Figuring out an app’s AppleScript incantation to do a particular thing is weirdly hard – hat tip to MacScripter / MS Word Insert Text for the Word insert syntax here.