Hello Gooh,
I had a request for the same thing a little while ago. When I sent my e-mail to them, I sent it in different files and they were over 5 MB in PDF format (Lots of evidence, lol). I received an e-mail back from them stating the following :
"We are unable to attach information to your file. Please resend your attachments in one single PDF format file, under 5MB.
Also, make sure that you include in your Email your full name, file number, date of birth and Unique Client Identifier (UCI) to help us identify your application."
Just follow that and you will be good, also I wrote what the e-mail was regarding and I included my wife's application information and my own just in case (I am sponsoring my wife)
Best of luck !