What is Post Templates?

Identify which fields to display in an approval request post.

REQUIRED EDITIONS AND USER PERMISSIONS
Available in: both Salesforce Classic and Lightning Experience
Available in: Enterprise, Performance, Unlimited, and Developer Editions

USER PERMISSIONS NEEDED
To create approval request post templates:
Customize Application
From Setup, enter Post Templates in the Quick Find box, then select Post Templates.
Click New Template.
Select the object for your template.
Click Next.
Give the template a name and description.
If you want this template to be the default for the associated object, select Default.
Add up to four fields to display on the approval request post.We recommend putting any text-heavy fields—such as Comments or Description—at the bottom.
Save your changes.