uploading a document

[Crackwillow]

I'm trying to upload a document to an online form. I've tried it in Word/PDF/Zip files and I think 'the cloud' and looked online for a solution. I am only just scraping by with my tech skills and this one has me pulling my hair out. It just keeps showing an error when I try to upload the doc. It's been 2 nights now of me trying... Any help is gratefully received.

Is the file beyond the maximum file size? Aren't you getting an error message that tells you what the problem is?

Can you copy & paste it into the form, or does it needs to be an attachment?

@Doyoumind No, just an error message but not telling me what's wrong.

@Cookerhood No it has to be an attachment.