I have a tooth that very decayed it is missing the top crowns of it. I believe it is a molar. It resembles a crater. Would that be a simple extract?

No. May not be extra table as a single unit. Because of the extent of the decay the roots may have to be removed separately. Reflection of gum tissue may be required to gain access. Integrity of roots may be compromised, complicating the procedure. Recommend seeing specialist Oral Surgeon ASAP.
Probably not but.... Removing a tooth as described may or may not require reflecting the gum tissue. First, we don't always know this in advance. What appears as a simple extraction can become more complicated and what would seem like a difficult surgical extraction often is simple. Also, cutting the gums often allows the surgeon to remove the tooth with less trauma and therefore less pain and swelling. So.
Not necessarily. It depends on the length of the roots, if they are curved, and which tooth it is.. Best bet is to let your dentist take a look. If necessary you will be referred to an oral surgeon.