For Direct Filing Entity (DFE) filings, a person authorized to sign on behalf of the DFE must sign for the DFE. 
Service providers may file on behalf of DFEs. You must make sure the DFE’s name is printed on the signature line of the draft Form 5500, attach the signed 5500, lock the filing and use Local Sign to select the "Single Signer- DFE" option. The signing screen will display the DFE’s name, but you will be able to enter your DOL credentials to e-file on behalf of your client. Please refer to the below article for further guidance on this process.
A DFE that has signature questions beyond the Form 5500 instructions may call the EFAST2 Contact Center at 866-463-3278 to be transferred to someone at the DOL who may be able to provide further clarification.