Do you mean "Jr." or "Sr." for Junior or Senior? They're called a SUFFIX. If you mean letters like "Ph.D", or "Ll D.", they're abbreviations for advanced degrees that this person holds - a "Ph. D", short for "Doctorate, Philosophical" (which very often has little to do with either Doctoring or Philosphy) is an advanced degree awareded in many fields. The standard sequence for post-secondary schooling in most of the west is: Bachelor's Degree (Arts or Sciences) - around 4 years Master's Degree - around 2 years Doctoral Degree - around 2, or more years, depending on subject The only other letters after names I'm familar with are things like "P.E.", which stands for Professional Engineer, or "CPA", Certified Public Accountant" - or medical ones like "FASB" and so on.
I believe that the answer to your question is post-nominal letters.
Names are always proper nouns and will always require capital letters.
pe = professional engineer
Gwendolyn Cornelius Kristofer
Associate of the chartered institute of building
The letters MASc will usually mean that the person has gained a Master of Applied Science degree.
Letters that stand for parts of a name are called initials.
Their surname.
It may mean United Empire Loyalist if they are Canadian
Using all capital letters for a name is called "acronym."
That is called a trio.
autograph