Is this problem in NP? I am new in complexity theory and have a doubt.
If you have a language (alphabet) L (for example {"a";"b";"Y","0","1","◄"}) and a Dictionary D (for example {"abY";"Ú■";"ba";"000001◄";"FFG","342"}) Output all the words in D that can be generated by the symbols in L So, for the example above a program will output: "abY";"ba";"000001◄" Question is: is this problem in NP?
Thank you in advance.
Your question makes a category error. Your problem is an enumeration problem ("List all the things with property&nbsp;X") but NP is a class of decision problems ("Does the input have property&nbsp;X?").

In any case, there is an obvious deterministic polynomial time algorithm for your problem. Just check each character of each string against&nbsp;$L$. If $L$ is fixed, this runs in linear time; if it's a part of the input, it runs in quadratic time.