If you have an email that you would like to use for future sends, you can save the email as a template.
In Salesforce Marketing Cloud Content Builder, how do I save an email as a template?
When you are ready to save your email as a template, to go the Save button on the top right-hand corner and select Save as Template from the drop-down menu.
The Save as template dialogue will open. Give the new template a descriptive Name.
For Location, a default folder will automatically display for saving your template. Click on the text to change the folder.
Note: Select a location from your business unit's folder within the Local Folders section.
Click Save. Your email will display as a template.