Sending a .docx file over Messages App

I received a text message of a word document from a family member stating that they have tried to send the document to other family members (android users), but get an error message. I am also an Android user and know that people can send me doc files over text message before, so I attempted to forward the doc to my mother (android user) and got the same failed message. I then attempted to save the .docx file to my phone, however, when I went into the Files app on my phone, the file was not there. I know we can send files through messages because I've received them in the past. All I want to do is send a .docx file over text to an android user from my iPhone. Is this a part of Apple and Google fighting with each other? My Aunt sent me this particular file and it worked for me because we both have iPhone 11 pro's. It still does not answer the question why I save the file to my phone and it does not show up in the Files app, nor does it answer why she can send .docx files to other iPhone users, but not android users over text. Any response would be greatly appreciated. Again, to be succinct, I am attempting to send a .docx file over text message to an Android user. I can send the .docx file over text message to other iPhone users, but it fails when sending to android users. Being an Android user also, I know for a fact that Android has the capability of sending and receiving .docx files over text message. Also, if saving a .docx file from Messages to my iPhone does not save it to the Files App, where does it save the file to?