Email Templates
Create Template
Follow steps 1 to 4 in the above screenshot.
In the above screenshot:
you can get started with a sample template
use the tools on the right sidebar to edit your email
preview your email on computer or phone
define up to 10 variables for later filling
Remember to save your template after you finish.
Use Template
In your flow, right click to create a Send Email Step, edit it, click on "Change Template".
Choose a template and map values for your pre-defined variables in the template.