Hello, there is a core gui component which is default in all roblox experiences. It can be accessed by clicking on a player’s name on the playerlist within an experience. It allows you to examine their avatar, send a friend request, block them or report them.
At times, if you want to add additional features or are using a custom playerlist then you would be able to create a custom version, which is what many games do.
-- Run in a LocalScript, ideally within "StarterPlayerScripts"
local StarterGui = game:GetService("StarterGui")
StarterGui:SetCore("AvatarContextMenuEnabled", true)