Dear Brock,
Good day! Thank you for posting in Microsoft Community.
The file content you defined in the File Content part in the Create File action may not be readable by Word for the web.
As a workaround, you may create a content type in the document library as a template of the file creation, create a list to record the form information, insert the library property with the Quick Parts option into the content type and finally update the file property with the list field values and map the file property values to the template content. All the process can be completed by the flow as follows.
For how to create a content type, you can follow the steps in Create or customize a site content type (microsoft.com).
Note: The article is also applied to the modern content type UI.
You can create the flow as follows.
For the created file showed in Word for the web, the embedded property values may not be showed in Word for the web directly but it is showed in the Preview mode.
You can format the Name column with the following JSON code for the users to preview the file in Word for the web.
{ "$schema": "https://developer.microsoft.com/json-schemas/sp/column-formatting.schema.json","elmType": "a","txtContent": "@currentField","attributes": {"target": "_blank","href": "=if(indexOf([$ContentTypeId], '0x0120') >= 0, '?id=' + [$FileRef], @currentWeb + '/_layouts/15/Doc.aspx?sourcedoc='+ [$UniqueId] + '&action=interactivepreview')"}}
Result:
Thanks for your effort and time!
Sincerely,
Cliff | Microsoft Community Moderator