on our site story points in company managed projects are tracked using Development story points

[SUVARNA Dixit]

We are using jira cloud and on project setting of Roadmap we are getting

on our site story points in company managed projects are tracked using Development story points

so its confusing for us which will be the correct story points

and why we are able to create new field as story points

[Mykenna Cepek]

To my knowledge, even an Org Admin cannot change the name of a built-in field in Jira Cloud. Admins can rename custom fields, but not built-in fields like "Story Points".

I suspect the only way that the built-in "Story Points" field could be renamed in Jira Cloud is with a ticket to Atlassian Support. And frankly I'm surprised Atlassian Support would do that. But maybe they did. One of your Jira Administrators would have had to request that.

Once that's done, then creating a new Custom Field called "Story Points" is easy.

Easy... but SO VERY WRONG. Never, ever do this! It's so confusing, and breaks so many reasonable Jira user expectations. And so much Jira documentation will now be wrong for your Jira site.

You asked "How this got changed?" and my answer above is all I can think of for "How?".

As for "Why did this get changed?" @Mikael Sandberg is right - you'd have to ask whoever changed all this in your company. Hopefully they have quit or have been fired, because it seems to me that you don't want them administrating your Jira.

[Mykenna Cepek]

I want to be sure I understand your question. Is this what you are asking?

     "Why can't we use our custom field for story points in Roadmaps?"

If that is your question, the answer is fairly simple. Jira uses the built-in "Story points" field in many places, and that cannot be changed. Examples include in the Velocity Report (and other reports), the special way that "Story points" show on the cards on the Boards and in the Backlog, and more.

Jira does not provide a way to specify a different or additional "Story point" field.

You can create additional custom fields in Jira. But they will be like any other custom field, just extra data in each work item. Creating a new custom field called "Development story points" does not do anything magical -- it's just another custom field.

[SUVARNA Dixit]

my question is why and how it got changed to Development story points from Story points as a default story points for Company managed projects.

"on your site story points in company managed projects are tracked using Development story points"- this is the notification i am getting on roadmap settings. (How and why? is there anything related settings modifications?)

few projects using story points and few projects are using story points(custom field) this i have observed . i am playing role as admin for few projects

[Mikael Sandberg]

So this is more of a question for your Jira admin on why it was decided to have a custom field for story points instead of using the built in one. I for one would have recommended against it since you loose features that comes built in when using story points, like the roll up. But there has to have been a reasoning behind this decision.

Jira is built so you can customize it by adding custom fields, but that doesn't mean that you do not need to think it through when adding new ones. I have seen plenty of examples where you have 10+ different fields for end date just to mention one example.

[SUVARNA Dixit]

yes, you are right  , but it was long back created . now what is your suggestion and my question is 

my question is why and how it got changed to Development story points from Story points as a default story points for Company managed projects.

"on your site story points in company managed projects are tracked using Development story points"- this is the notification i am getting on roadmap settings. (How and why? is there anything related settings modifications?)

few projects using story points and few projects are using story points(custom field) this i have observed . i am playing role as admin for few projects

[Mikael Sandberg]

This is something that needs to be asked internally, if the person that made the decision is no longer with the company or no one can explain why then I would consider changing it back to use story points. You could aways use automation to copy the value over from you custom field to story points and then let every one know that from now on we are using story points and nothing else.

[Mykenna Cepek]

(moved to a separate answer)