As Chris mentioned, "여기" is the most basic "here". The "에" that gets tacked on is actually a particle that indicates location, kind of like 'to' (but not exactly the same). So, for instance: Q: Where are you going? --> 어디 가? A: (I'm) going to school. --> 학교(에) 가 Another example showing how it's a bit different from 'to'. Q: Where's my pencil ? 연필이 어디 있어? A: It's here. 여기(에) 있어. In casual conversation the "에" is often left off.

it is like ここ and ここで/に where 에 is equivalent to で/に as the location particle

é==에 تحدد اكثر المكان يوغي==هنا يوغي اي==في+هنا

여기 means exactly here but 여기에 means here is (something) or over here.