Twitter is a social media site where people post status updates or make short quick posts.
There is a section on the user’s profile for personal information but you are more likely to find age confirmation in tweet replies. Clicking the “Tweets and Replies” tab to see the replies - quite often someone will post their age in response to a question, or when making a birthday announcement.
Additionally you may come across racist and homophobic tweets. You don’t have to go through their entire twitter feed, but scrolling down a fair way will give you a good indication of someone’s personality and if they are going to be a good fit for the server.
With TikTok probably the thing you are looking at are:
We don’t expect you to go through all their videos to determine any of this, but if you take a look at their profile and check one or two videos. That will usually give you a good idea of age and personality.
With instagram probably the thing you are looking at are photos to see if the applicant looks over 16. Instagram does have a section in the user profile to add text but it’s not often people will list their age there. We definitely don’t expect you to go through the comments on posts. Just a cursory glance at the profile and a few photos will suffice.