Sign your name as "personal representative".
See https://www.irs.gov/publications/p559#en_US_2019_publink1000201744
Signature.
If a personal representative has been appointed, that person must sign the return. If it is a joint return, the surviving spouse must also sign it. If no personal representative has been appointed, the surviving spouse (on a joint return) signs the return and writes in the signature area "Filing as surviving spouse." If no personal representative has been appointed and if there is no surviving spouse, the person in charge of the decedent's property must file and sign the return as "personal representative."
