Please see  this article for details on email restrictions.

In order to be able to stay within the size limit of 25mb per email, it is suggested to zip the files that are being attached that are too large. To do this, please see the steps below:

1. Go to the folder containing the files you want attached in the email.

2. Select the file/s, right click and select Send to Compressed (zipped) folder

https://cdn.extendoffice.com/images/stories/doc-outlook/auto-zip-attachments/doc-auto-zip-attachments-1.png

2. Right click the compressed (zipped) folder, and select Send toMail recipient.

https://cdn.extendoffice.com/images/stories/doc-outlook/auto-zip-attachments/doc-auto-zip-attachments-2.png

3. Now the compressed (zipped) folder is attached in a new email and ready to be sent.

https://cdn.extendoffice.com/images/stories/doc-outlook/auto-zip-attachments/doc-auto-zip-attachments-3.png

If however the size of the zip folder still exceeds 25mb, it is advised to use one of the following services to store the file/s and use a link within the email to send to your recipients.

Service

Accepted files and advantages

Google Drive

Provides 15 GB of free storage along with paid services to increase space

Dropbox

Free 2 GB and the ability to earn up to 16 GB of free storage.

YouTube

If you want to attach a video, there is no better online service than YouTube. Also, what most people don't realize is that YouTube videos can be made private which means only people who you share the video link with can view it.

OneDrive

Windows 10, Windows 8, and all Office365 users have access to OneDrive, which offers 5 GB of free cloud storage. If you have subscribed to Office365, you have 1 TB of OneDrive storage available to use.