What is a suffix for a name?

Greetings to you, Li_Mei.

A suffix in a name can be a letter, letters, or a word that comes after the last name which is part of that person's name. Examples of this would be Junior (Jr.), Senior (Sr.), I, II, III, IV, etc. It goes at the end of a name and generally follows a comma.

This suffix is usually used if a person's name is the same as someone in the family. The name could be repeated multiple times in the family, hence the use of I, II, III, IV, and so on.

For example:

John Michaels, Senior(Sr.) or John Michaels I (first in the family to use this name) 

John Michaels, Sr.'s son could be John Michaels, Junior(Jr.) or John Michaels II.