I just want to download the new ios and have 7GB space in my storage why I couldn’t download the IOS?

If this is your personal device then you can update your device with the current iOS

Know how to...

• Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
• Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If this is your corporate iPhone, it is important to reach out to the system administrator of your corporate. They will be able to assist you with any issues or concerns related to your device.

However, if it is your personal device, there are a few things to consider. Firstly, check if you have any profiles installed by your corporate, organization, enterprise, or school management. These profiles are typically used to manage certain settings or restrictions on your device.

If you do have a profile installed, and you no longer wish to keep it, you can follow the steps provided by Apple to remove configuration profiles on your iPhone. By doing so, you will eliminate the profile and its associated settings from your device. Install or remove configuration profiles on iPhone - Apple ...

In case you need further guidance or encounter any difficulties during the process, it is recommended to contact the system administrator of the organization that provided the profile to you. They will be able to assist you in removing the profile or addressing any concerns you may have.

You may get better and prompt responses if you may kindly provide the iPhone Model that you have and the iOS version if it is known to you and re-post.

With the limited information that you have provided, It is hard to even guess the problems faced by you. 

You may get faster and better responses to your query by --> Writing an effective Apple Support Commun… - Apple ...

Please re-post with detail so that someone else can help.