Hi, respectfully I suggest you read the Instagram help center (their spelling) page about privacy and safety. it details controlling visibility, good posting practice etc. to keep yourself as safe as possible. as for user ID etc. you can click through to other sections and learn about that too.
I don't personally use Instagram or any other form of social media these days. I used to have a Google+ profile and over 250k following me for my Cars and Motorsport content. Although Google asked me to join their Creator Program because of this and the quality of my collections I declined. It got to the point it was a laborious task coming up with fresh content, not just blanket re-sharing which a lot of people tried with my stuff and got abusive when I disabled it in the end, dealing with posts from idiots, reporting spam etc. so I jacked it in entirely and deleted the contents and my profile.