I assume you're asking about a Quitclaim deed and a deed to the property has nothing to do with the mortgage although there is a possibility that the contract for the mortgage prevents any transfers of the property without the lender's permission. That wouldn't really become an issue unless the mortgage isn't paid though.
You usually want to avoid Quitclaim Deeds. With the advent of the internet many people try to do Quitclaim Deeds themselves but many times they are a mistake that will cause serious, and expensive, problems later. First, no non-lawyer should ever do a deed. Actually, no one, including lawyers, who don't do a lot of deeds should ever do a deed because they are too easy to make a mistake on and if you make a mistake it generally isn't caught until much later and can then cost a fortune to correct if it can be corrected at all.
In addition, many title insurance companies won't issue title insurance on property where a portion of it was deeded by way of a Quitclaim Deed. If you can't get title insurance then it essentially makes the property unmarketable and worthless since you can never get financing without title insurance.
A Quitclaim Deed is not the same as a Warranty Deed for a variety of reasons. Some websites, written by people who don't know much about the law, state Quitclaim Deed are "just as good" as Warranty Deeds but that is an absolute false statement. The QC deed can pass title but it does so without guaranteeing that the title is clear, that the person owns the title, etc. They are actually used only in "last ditch" situations where no other form of deed can be obtained or where the person can't prove they own any shares of the property.