Form G-1145, E-Notification of Application/Petition Acceptance, is a one-page form used to request a text message and/or an e-mail confirming that USCIS has accepted your application/petition. It is not mandatory. You do not need to use Form G-1145 unless you want to receive the mentioned e-notification from USCIS.
There is no filing fee for submitting Form G-1145. Simply clip the completed G-1145 to the front of the application/petition you are filing. For example, you can use it with the following forms: Form I-90, Form I-130, Form I-485, Form I-765, Form N-400, etc.
However, currently this service is only available for forms filed at one of the three USCIS lockbox facilities located in Chicago, Illinois; Lewisville, Texas; and Phoenix, Arizona.
Please also note that receiving an electronic notification with G-1145 form serves for informational purposes only. It does not grant any type of status, unlike Form I-797C, Notice of Action, that you will receive from USCIS afterwards. The received Form I-797C, also known as a receipt letter, can be used as a proof of pending application/petition and ongoing procedure under your case.