If you see the message "This file exceeds the maximum size, please try to upload a smaller file", the file is too large for the application's upload limit. Here's how to make it smaller.
If it's a photo
Phone: Some phones save photos at very high resolution. Take the photo again at a lower resolution, or use your phone's built-in photo editor to reduce quality.
Use a smaller camera setting — most phones have an option to switch from a high-resolution mode to a smaller one.
Compress the photo using a free image compression tool.
If it's a PDF
Try saving the PDF at a lower quality (most PDF editors have a "reduce file size" or "compress" option).
If the PDF has multiple pages, split it into smaller chunks and upload them separately.
If you can't reduce the file size
If you can't reduce the file yourself, contact your property manager — they can accept the file directly or share a different way to send it.