Attach resume using a mac

An online résumé will be stipulated to be in Word .docx, or PDF format, and never .pages. The website will likely use JavaScript to allow you to locate the file on your Mac, and then upload it as an attachment.

The small print on the website may also tell you that these attachments must not be larger than a specific size (e.g. 100KB). That pretty much rules out the larger Word document exported from Pages applications older than v6.3 on Sierra or High Sierra. If the specified size is exceeded, the upload will fail.

You can export to Word .docx from Pages versions older than v6.3, and then open and save the File again as Word .docx either with the free LibreOffice, or MS Word. This process will generate a Word document smaller than 100KB.

how do they want you to attach it? through email? through a website?

if through the providers own website try it using another browser. Make sure the browser is up-to-date. The developers of the site are responsible for making their site work with browsers, not Apple's job to make sure every developer who can't be bothered. If you are continually running into an issue with this contact the developers support.

if you are having an issue with email over a web browser email try another browser (e.g. gmail.com, yahoo.com, exchange.com)

if you are having an issue with Apple Mail are you getting an error message about the attachment.