Since only hit 80 campaign “leveling” story quests can skip.
But after only 80lvl max for campaign quest dont have one.
I wished my alts could it skip it as first chara done.
I really hope in Season 2 or 11.0.7 patch
Btw: I mean this https://imgur.com/a/yE4h7pt could skip
I didn’t have to repeat the campaign on alts. Did you miss a part on your first char maybe?
I knew it…
I was mean something call “the war within” campaign could skip
https://imgur.com/a/yE4h7pt
Since Brann dont have this for skip
So, nobody know when we can skip ““the war within” campaign? About I linked screenshot
and tell me exactly why even would you want to skip this in the first place ?
does anything is gatekept ? nope
does this prevent you from entering new zone ? nope
does this prevent you from doing story mode ansurek to get heroic crest ? nope
does it preventing your progress of your char in any kind ? nope
is your renown vendor locked behing it ? nope
so let me ask again, why ?
You’re not going to be able to skip the campaign unless you’ve done it once. Other wise it defeats the whole point of the game.
Once you’ve done it once you don’t need to take it again. No need to skip.
“Becuase everything must be 100% complete before I can play alts” 
You can skip the Dalaran intro quests and the first part of TWW storyline but the follow-up story can’t be skipped yet.
This was the chain that became available after the initial launch. I have no idea why they wont let you skip it but that is how it currently stands.
What’s the use of ‘skipping’ them?
They’re just quests, you don’t need to do them.
They’ll probably be skippable once the next max level campaign chapters get implemented (10.1. + 10.2); at least it was that way during DF.
I have not repeated the campaign on alts unless I wanted to. But i dId complete it on my main.
I could skip the intro by talking to Thrall or Jaina in Silithus or Dalaran, depending on my faction. Then it teleports me to Dornogal, where I can choose a zone from a map near Brann. I can choose a zone and do the story and sidequests. Some alts I did just side quests. Others did dungeon spam.
Yes, this is the way it goes on alts. But just to clarify, you don´t actually need to talk to Brann at all, you can just go about your business leveling /crafting /whatever and talk to him when you reach 80 to skip the leveling campaign. Or don´t, even that isn´t necessary to participate in any and all forms of content you may desire. 
Seriously, once the first char has completed the leveling campaign, the others have completely free reign to do more or less whatever they want, including never interacting with any NPCs. 
Yes ofc. I didn’t bother at all on some.
Same, I talked to him @80 on anything that´s a “Main alt” jsut to remove the question marks, but the vast majority of my chars couldn´t care less what any NPC that isn´t teaching /selling them crafting recipes has to say 
why would you want to skip the war within campaign first time doing it ? do it atleast once .
Once you have completed the campaign on one character skip options become available.
Skip 1 is when you enter the Heart Chamber and talk to either Jaina or Thrall. This skips the INTRODUCTION quest in Dalaran and the crash of Dalaran. Should you enter dalaran talking to Khadgar also gives you the option to skip the introduction quests. It teleports you to the explorer’s league “main base” in Dornogal where Brann will give you a quest to let you choose your startingzone. By default you always start in Isle of Dorn. The map table allows you to choose a starting point but requires you to go through all the main campaign quests. (The quest icon with the shield motif around it).
Skip 2 becomes available when you hit 80 and lets you skip the main campaign quests up to the point of finishing the main quest line in Ajz Kahet. Again you talk to Brann and he gives you a failsafe of are you sure you want to skip the remaining campaign quests and of you still say yes he accepts and tells you that xalatath can more or less sit in limbo until the next patch. It still allows you to do the follow up main quests to complete the Earthern dwarf race unlock. It should start off with you inspecting the new stormhawk riders with Thrall.
So basically to skip all main storyline quests you need to have at least 1 character complete the 4 main storyline chains in each zone and then have it at max level to skip the remaining main storyline chains on any alts. Non campaign quests and chains won’t be affected by these skips.
The game will not allow your 1st character to skip all quests because for the simple reason that Blizzard quite rightly wants you to experience the story of why you are there.