Out of the box, only Administrators can use Gravity Forms. That is usually wrong for real sites: the person who writes the content is often the same person who should build the contact form and read the submissions, but handing them an admin account to do it is a bad trade.
This plugin gives the Editor role access to Gravity Forms, and lets you decide precisely how much.
On activation it grants a sensible starting set: Editors can build, preview and delete forms, and view, edit, export and annotate entries. It does not grant anything that changes site configuration, and it does not grant entry deletion. From there, a single settings screen under Forms → Settings → Role Permissions turns each individual capability on or off with a checkbox.