With ezMail Signature you can push email signature to employees of your domain simply from a Google Sheets.

Admin install tips : access is restricted to Super Admin and Delegated Admin so it is better to install the add-on for admin only based on a Org Unit or a Google Groups.
If you need a wider access contact us for white listing users : https://ez34.net/contact

******** How it works ******** 

Just 3 clics to push new signature :
1. Setup sheets
2. Retrieve users information based on profile by Organisation Unit or the whole domain.
3. Put your template in the field

That's all clic on button to push signatures.

******** More Details ******** 
We retrieve user profile information in the sheets to let you view and modify if needed details.
You can select a specific Org Unit or select the whole domain.

******** Template Details ******** 
In your current HTML Template just replace the values by short code i.e. {{SHORT_CODE}}.
Values supported : EMAIL, FIRSTNAME, LASTNAME, TITLE, COMPANY, COSTCENTER, DEPARTMENT, WORKPHONE, MOBILEPHONE, WORKADRESS

+ 5 Custom Fields for specific data not present on the G Suite domain. 

>> ezMail Signature also support dynamic field
For example you can set a mobile icon before the phone number. If the user have a phone number icon will be displayed if not the icon will not appear.

To get help check this page : https://github.com/St3ph-fr/ezmail-signature-template/

******** Paid App ******** 
ezSignature comes with a 20 credits free to test the application.
Then you will have to buy extra quota got to 'Extend quota' menu.