Smart button which is developed by Scott has many buttons introduced in his soluion. Among them one of the button is Run Webhook. Solution can be downloaded from here.
Download the managed solution and import it into your CRM instance. Once imported Create new solution and requirement entity on which you want to add button to call flow webhook.
Create Flow as HTTP trigger and I have added action to update CRM Account record Name.
Once flow created, click on save and copy HTTP Request URL which we will use while configuring the ribbon button.
Now open Ribbon workbench Tool->Open solution ->Drag and Drop Run Webhook button from smart button list.
Provide Button Title, Webhook URL and other details as provided in screenshot.
Once published, go to entity form and click on button. Now Once done you should see account name updated.
Hope this helps! Power platform my friend.