I believe this is what you’re looking for (not entirely sure since your question wasn’t very descriptive).
NSURL *url = [NSURL URLWithString:@"instagram://user?username=USERNAME"];
if ([[UIApplication sharedApplication] url]) {
[[UIApplication sharedApplication] url];
} else {
// handle the issue
}
Otherwise, see the instagram api here.
solved How I Add Button Go To The Instagram? [duplicate]