You can easily transfer videos to your phone by using a free file hosting service such as Dropbox or Google Drive. Let me briefly show you how to do this with Dropbox.
1. Go to dropbox.com and login with your account. If you don’t have an account already, you can create a new one.
2. You can create a new folder and upload a video file from your computer.
3. Launch the Dropbox app on your phone and visit the same folder to download the video to the phone. If you don’t have the app, you can download it from the App Store for free.
Google Drive works pretty much the same way. You can also do this with AirDrop if you're using a Mac and an iPhone.