Redmine

you can probably do this by creating a plugin or something along those lines.
if you don't know how to make a plugin, you will have to ask someone...

but this post has VERY LITTLE information for anything

Please specify more - what exactly has to be achieved?
Most likely this is something to be done with custom development.
Please contact me at support@redmineup.com if you need more detail on this point.

Hi! James and Andy,
My requirement in Redmine is that when I create an issue and assign it to someone, the assignee should receive a list of all members added to that project. Additionally, there should be custom placeholder fields next to each member where they can provide remarks. Furthermore, when the assignee closes the ticket, the data (including remarks) should be stored in the database.

Detailed Explanation
Issue Creation: When you create an issue in Redmine.
Assigning the Issue: When you assign this issue to a specific user.
Notification to Assignee: The assignee should receive a notification or have access to a list of all members who are part of the project.
Custom Placeholder Fields: Next to each project member's name in this list, there should be fields where the assignee (or other users) can enter remarks or comments.
Data Storage on Closure: When the assignee closes the ticket, all data, including the remarks, should be stored in the database.

I am attaching image for reference.