what is easyier class in the game so far so i can create my free 3rd char?
Converse with fellow players
I don't think there is an easiest to use character. Save your 3rd character slot until you find a race / class you want to try.
I'd recommend choosing a race/class/or gender that you haven't used before. I tend to do that so I can hoard more outfits from mission pass and so your alt can use a different mag than your main. It's a fun little challenge for me cause I pick classes I'm not that great at. If I wind up loving the class after all, I'll take what I learned from the alt and apply it to my main. So an alt can be a great "test" character for whatever you might want to try. Also there is little to no reason to get an alt past level 50 for the weekly quests so you don't have to spend a lot of time on them if you don't want to. Just make what you want =^.^=
Summoner, there's more involved in building the pets (though gear doesn't matter too much for your character), but it ends up with you not having to put much effort in fights, since your pets can get the aggro from enemies while you're pretty far away. You basically just spam a few buttons all day then, just making sure to heal the pets so you don't have to wait for them to recharge. I personally find it boring, but hey it's easy to play as them.
Hero, Phantom and Étoile (the scion classes) are definitively easier to play because they don't have a ton of ability management to keep up with; Episodes 5 and 6 placed an increased demand on fast reaction times and precise play and these classes have few PAs with more versatility (such as Hero automatic weapon type switching) which frees up time and concentration to perform better at more accessible player skill levels.
The catch is they all need two other classes to be levelled to 75 first, so this is not an option for new players. If you're just looking to do that unlock them, most other classes should work fine. Summoner might be useful because collection folders giving level 100 pets should give a reasonably capable entry level without needing to gear up. Additionally it can be used to level the second class a little faster before Summoner hits 75 thanks to doubling the EXP gain of subclasses.
Beyond that... Fighter and Gunner are probably not ideal? Since they require a degree of equipment setup and skills (both class skills and player competence) to perform well as which isn't worth investing in if you just want a stepping stone to the scions. Force and its need for some skills might also fall in this category. Techter would be a little easier to set up and MPAs will like seeing your presence, meanwhile Hunter and its survivability shouldn't be too difficult to get some use out of until you reach 75 for scions.
If you don't want to go the scion route to built-in streamlining, it probably depends on the type of content you want to do and how far you want to take it. If you're more about Time Attacks (with a view to Rankings) you might want to go Force or Braver as their PAs and techniques give vast natural advantages especially at higher level of play. If you want to focus on damage for UQ content, those can still do well alongside Fighter and Gunner. If you still want a degree of safety in exchange for raw takedown speed there's Hunter, Ranger, Techter and Summoner which offer varying degrees and flavours of each. And if you want to be a jack of all trades (except ranged damage) but master of none, you've got Bouncer.