Suffix is a correct term in linguistics. It refers to a letter or group of letters added to the end of a word to change its meaning or grammatical function.
For example:
* -ing (running, playing)
* -ly (happily, slowly)
* -er (bigger, faster)
Pruffix is not a real word. It seems like a misspelling or a humorous invention.
It's possible you might be thinking of prefix, which is the opposite of a suffix.
Prefix is a letter or group of letters added to the beginning of a word to change its meaning or grammatical function.
For example:
* un- (unhappy, unkind)
* re- (redo, rewind)
* pre- (prepaid, pre-flight)
So, remember:
* Suffix: added to the end of a word
* Prefix: added to the beginning of a word