This does not appear to be live in our instance, unless I'm missing something. Our projects are Type = Company-managed business, so I'm guessing that should be the Project Type (i.e., business project) you're referring to. I've tried navigating to Project > Project Settings > Issue Layout and have edited the issue layout to include all fields. I've also confirmed the underlying screen has all of the fields, including the optional ones as well. Yet the Create Linked Issue still only displays the Required Fields. Is this not live yet or does project type "Company-managed business" not equal "business project" in this context? Any help would be appreciated. Thanks!

Happy New Year, everyone! May it be filled with joy, success, and - who knows - maybe even some miracles. Like Atlassian resolving to fix this bug. We can dream, right?

e3ea4b6190c9 
As long as you have mandatory fields, it doesn't matter if you use the create issue screen or a 4th screen.
You'll need those fields on the screen as you can define them only once as mandatory.
So we're talking only about showing optional fields on the screen or not, which you don't have to fill out, if you need to quickly raise a ticket.
In your case you would need a screen with a minimum of fields and the option to not care for the mandatory fields, which are not on the screen and create an issue without them.
As Atlassian couldn't manage over 8 years to just pop up a screen they already have and pre-fill the linked issue field there, your request really means rocket science to Atlassian and at least 10 more years to wait, i guess...

I do not fully agree with the latest statements, even if I can understand where they come from.

I'd expect a 4th screen in the schemes for create linked issue next to "view, edit, create", by default taking the create which would cover the before mentioned needs. 

But there are some cases where a little difference between linked issue and create issue screen is needed, easiest example is the linked issue field itself. Also there are cases within support for example, where an agent just needs to "quickly" create a linked task for DEV while talking directly to a customer and cannot provide the as needed marked fields DEV usually would require!

I agree with Bernhard G., that the best would be to just call the create issue screen for create linked issue and prefill the fields linked. That way it would be easy for any user, even with limited Jira knowledge, to create a linked issue without any complexity.

So 8 Years without a solution.

The fields are already there, they are just hidden, you can see with developer tools..

on "create-linked-issue-dialog" > "jira-dialog-content" > "qf-container" > "qf-form" > "form-body" > "content" > see the style of every field.

if you put "style="display:none"" to "style="display:block"" it works just as expected ...

Is it that hard to just display those fields?

Currently this is blocking us really much.
In Jira Server we where able to link Issues with "Create Task" in a normal issue. There we saw the "Create Issue Screen" and not the "Create linked issue Screen" that's why we did not had the issue there.

So it's just standard functionality that is not available in Cloud.

It's already working for the normal issue screen that the shown fields depending on the project you choose.
In my opinion it would be the easiest and best solution to use the create issue screen for create linked issue too and just fill out the issue link automatically.
At least for us I don't see any use case where I would need a different screen to create a linked issue than create an issue. It should just fullfill me the linked issue field - that's enough.

I guess that would already help a lot of people and couldn't be the rocket science as the screen already exists and just needs to automatically fullfill one field when it gets opended. Can't comprehend why this issue is already waiting since 2016.

@Atlassian: Still no plans for that?

Also looking forward to this one, it'll save a lot of manual effort longer term

Looking forward to it