The short answer
If the owner was the only name on the deed, the estate opens with the Register of Wills and a personal representative is appointed. Once that person has Letters of Administration, the house can be sold, even while the estate is still open.
Probate starts in the county where the owner lived. The Register of Wills opens the estate and appoints a personal representative, usually the person named in the will or a close family member when there is no will. The Letters of Administration that come with the appointment are what the title company asks for at closing.
A Maryland estate often takes most of a year to settle. Creditors have six months from the date of death to file claims, and the personal representative should not pay everything out before that window closes. The house does not have to wait for all of that. It can be sold during administration, and the money goes into the estate until it is distributed.
Some houses never go through probate at all. A home held jointly with right of survivorship, owned by a married couple as tenants by the entirety, or placed in a living trust passes straight to the surviving owner or the trust. In those cases the sale can move as soon as the family is ready.
Wherever your estate is in that process, we can make an offer now and set the closing around the paperwork. For the full walkthrough, including taxes and who has the right to sell, read how to sell an inherited house in Maryland.