Hello, I recently acquired The Sims 4. I don't know where to start and I want to know what are the must have mods that you guys can't play without.

Hello, same here. I started playing ts4 myself almost a week ago!
I haven't downloaded mods at all. CC, to be honest, and I think that it's a nice point to begin with!
I'll follow this thread because I'm so curious.

I don't know your prefered playstyle but I would say THE must have mod is MCCC https://deaderpoolmc.tumblr.com/
I don't know if you played TS3 but that mod is similar to nraas.

If you want to spice up your game with adult content there is wicked whims (not really a must have but because as I said I don't know your playstyle it is a must have for you)
but I don't post a link for that because it's on an adult oriented site.

The next "must have" for some people is the simulation lag fix http://modthesims.info/download.php?t=598676
personally I don't use it because my game runs smooth and fine without it.

I guess that are the most "must have" mods I could think of.
of course there are other mods for small thing you would like to change like no friendship loss from hissing vampires or stuff like that.

Welcome to TS4. There are more people on it's main forums but it is sad how main forums limit new users (no editing or starting your own thread stupid rules). Everyone wants to post on the main forums. Here I think there are some forum trolls but still some nice people. I will do my best to help because I started playing not long ago.

1.
MC controller is very much worth the time to invest in. MCCC https://deaderpoolmc.tumblr.com/
It covers a lot - all in one mod - and may seem overwhelming but it is nice to give you more control over your hood. Remember to back up!

2.
The next one is cosmetic and you must have aliens (Get-To-Work). But it's nice to have elves so this one: http://modthesims.info/d/588257