Yes, there are two ways to use GIFs in an email.
If you want the GIF to move in the email, create it on another platform, then save it as a GIF and upload it to the email via an image block.
You can also use a GIF as a thumbnail that, when clicked, redirects to the GIF itself by linking its URL to the thumbnail image.
Once you have started a new email, here is how it works:
Add an Image Block to your email
Click on the Image Block and you will see the information about this specific picture pop up on the right
Under the 'Build' option, click 'Replace' and choose the image you would like to be the thumbnail for this GIF
Now, to add the link for the video, click 'Link Type'
Choose 'Web Address'
Paste the URL to your video in the Link box below
Save, then close, and you will have a GIF connected to the picture in the email.