1- can i request an interview in my application?
2- is it allowed to travel to certain country just for an interview
Not all schools require interviews - in fact, the majority of schools do NOT require interviews.
- traveling to the USA for an interview is a stupendous waste of money. In 98% of cases, even for schools that have them (very few), they mean very little.
Also there are other interview options such as using Skype that won’t involve travel. My S and D both did Skype interview for grad school and it worked out just fine.
OP: really only some very selective schools offer interviews. Based upon your prior posts, you should craft a target college list that is very realistic and without many “reaches” i.e. schools that will conduct interviews (which still don’t matter in 98% of the time, in my opinion)