Every company handles file attachments differently. This means one company might be able to accept a large file, but your mail server will not send large files. It could also be the other way around. This becomes a tedious process if one doesn’t have the resources to work within these limitations.
With that being said, I am going to assume that all companies have a 5MB limit on sending and/or receiving. I will put all of the files in a ZIP file, and look to see the size. If the size is less than 5MB, I will include it into the email I am sending you. If the file size is larger than 5MB, then I will upload the file to my host and provide a URL to one of my sites. Most likely, it will be a website that does not have actual content such as my frankpilone domains, or my redirects. The file name will be the date and time of the ZIP file, and will remain on my site for 1 month which it will be deleted afterwards.