When using the End User CSV Import ("Issues" > "Import Issues from CSV"), it seems the fields available are based on the create screen of the project. Recently, I had an end user who was trying to import based on issue type and could not. I tried as an end user and also could not.
 

 Steps to reproduce

1. Log into Jira, access a project that has "Create Permissions" for the user
2. Verify the project does not have the "Issue Type" field on the create screen
3. Navigate to "Issues" > "Import Issues from CSV"
4. Attempt to import a csv with the following information:

   Issue Type,Summary,Epic Name
   Bug,Test Issue 1,
   Task,Test Issue 2,
   Task,Test Issue 3,
   Epic,Test Issue 4,Test issue 4
   

Expected Results

The "Issue Type" Field should appear as an option

Actual results

The dropdown will be missing the "Issue Type" field.
This prevents users from creating issues as the type of their choosing.

I think it would be really useful if the "Issue Type" field was always selectable on the end user CSV import. I can see the case where users should only be able to import whatever is on the create screen (even for system fields), but I do believe the "Issue Type" should be the one field that is exempt from this rule.

Also, I think it would be very useful to update the documentation to include a note mentioning that end users "can only map fields that appear on the create screen".