Documents received through RTI can used as legal documents to register complain? Or it is just for reference?
You can use the certified copies of documents obtained under the RTI Act in other legal proceedings and/or complaint proceedings. Such documents are public records maintained by the public authority.
Certified Copies of document received under RTI Act, 2005 is Secondary Evidence under Section 63 in The Indian Evidence Act, 1872. Thus, you can use certified copies for any legal purpose including filing case in Courts or lodging complaints.