Imovie app is not free anymore

If you currently have an Apple Music subscription active, you will not be able to change regions.

If your iTunes store region is set to a different one than it was when you originally activated the iPhone, then that is the reason you cannot find the Apps for free.

Change your iTunes Store country or region - Apple Support

What you need know before you change your country or region

When you change your iTunes Store country or region:

• Update your billing address. When you change your billing address, the primary address for your Apple ID and your other Apple services, such as the App Store and iCloud, automatically updates.
• You might need to update your payment method. For example, only German credit cards can be used to buy content from the German iTunes Store and App Store.
• Your Purchased section no longer shows items that you purchased from the store in the previous country or region.
• You won’t see the items from your iCloud Music Library that you matched, uploaded, or added from the store in the previous country or region.

Did you buy this iPhone new?

iMovie is only free with a purchase of a new device. Otherwise it has never been free.

If you bought the iPhone second hand, then iMovie was free for the first owner, not you.

If you did buy it new, then try finding it in the Purchased section of the App Store app.

Get Apple apps for free on your iPhone, iPad, and iPod touch - Apple Support

None of the Apple apps (Pages, iMovie, Numbers, Keynote, GarageBand) are free with the device. They are free with the first activation of a retail new device purchased from Apple or an Apple Authorized reseller. Once activated, those Apps are then tied to the AppleID of the person who performed that first new device activation. Any subsequent owners or activators of the device are not entitled to those apps for free and will need to purchase them.

It is also technically illegal and a violation of the software license to sell an iphone with one's purchased apps still installed on it. The owner is supposed to wipe their purchased apps off the device before selling it.

If yours was the AppleID used to initially activate that phone when new, yes, you can download them again as often as you wish using that same AppleID. You will not be charged to do so as your AppleID owns the rights to use them on as many devices as you own, now and in the future.

If anyone else first activated that phone with their AppleID, then the apps will be tied to their AppleID. Note it has nothing to do with the purchase date or whomever purchased it. The apps are tied to the first person to Activate it with a valid AppleID.

Go into the Purchased section of the App Store by tapping on the Updates tab at the bottom, and then on Purchased.

If the Apps were associated with your Apple ID at any point, they should be there, and can be downloaded for free.

If they were associated with a different account, then you cannot find them unless you log in to the store with that account.

Note that if you do log in with a different account, and download past purchases from it, you will lock the device to that account for 90 days.

If the Apps were not associated with your account at any point, you will need to buy them.

You can try to sign out of the App Store, and sign back in with the same Apple ID and see if that refreshes the association and lets you get them for free.

You can try to simply buy it and see if it charges you for it. But you understand that all sales are considered final, and Apple may not refund you your money if it does charge you. You can report an issue with the app if it does charge you and request a refund for it at: http://reportaproblem.apple.com

You only need to change the region back long enough to re-download your past purchases from that region. Once those are installed, you can set it back to your current region. You can use purchases you made from one region in another, but the online store fronts are region specific (for many reasons - copyright laws, tax laws, etc), so your purchase history is going to be store/region specific.

it's not pre installed it's free for purchase of a new iphone

but if it was deleted to another appleID then yours and it's a used phone you don't get it free

Yes, purchases are region specific, so you need to change your region back to get the purchases you made in another region's store.