For that you need to take the consent of the respondent first,if he agrees then you can put his name

Maybe it depends, Aikaterini? If somebody was your expert source and they showed their helpfulness and competence, it's nice to give them credit. For example, "The ABC monument is visited by 20,000 people each year (Name, personal communication)." But if somebody said something they maybe shouldn't have, it's nice to go out of your way to make sure they can't be identified. For example, I wouldn't say, "Mr. Smith wishes people from XYZ would stop visiting ABC because they always make a mess!" Maybe Mr. Smith just had a bad day, where somebody from XYZ made a mess, and when he feels better he'd realize he was stereotyping and didn't really mean it. Personally, I feel no matter how important our research is, kindness matters more. Nobody's life deserves to be ruined (e.g., lose job) because we happen to notice their worst moments. If you're citing something in between, maybe go ask the person if it's okay. From another perspective, if the person was a participant in your study, different rules could apply. Like in my country (United States), there's a whole consent process for participants and it includes rules about confidentiality. So definitely follow the rules. There's probably an office at your university who you can ask about any rules. I hope your study goes well! ~ Katie

In my opinion, researchers have the right to voice their opinions. However, it is necessary to be objective and have evidence.