I do have a Dropbox account and have used that to transfer files to colleagues. I started with the free account but quickly exceeded my minimum storage space, so I upgraded to a paid account with much larger file space. I have also used We Transfer many times with great success. https://wetransfer.com/ This is a free service for files up to 2GB. Just enter the email address of the person you wish to send the file to, upload your file, add a message to the recipient, and click Transfer. The recipient will receive an email with a link to download the file. Easy Peasy...
I believe you can also create your own link and send it in a personal email, or copy it to a forum post, if you wish to do it that way.