Can you access your resume document from the Pages App? If you can, prior to attempting upload to Indeed, you might be well advised to export the Pages file as either a PDF or Word format document - as these are often preferred by Recruiters/Employers.
Print and Export are accessed from the associated Document menu.

When exporting/saving your document, be sure to save it somewhere that it can be easily found in your iCloud storage, or locally on your iPad. Having saved the exported file, switch to your Files App - and verify that you can locate the saved file.
Presumably you will be accessing the Indeed website using Safari. Having demonstrated that the file an be accessed using the Files App, you should also be able to navigate to the file when using Safari.