I’m using iPhone 6plus, needing to update my iOS 12.5.7 to new version, i can’t! Need help with it please.

Hi Ezechiel27,

welcome to the Apple Community :-)

Re: "iPhone 6Plus: needing to update my iOS 12.5.7 to new version"

You might want to check out the advice in this discussion thread.

(It has a similar request to yours)

How to update my iPhone 6plus iOS 14 - Apple Community

Apple support's article:

iOS 13 and iPadOS are compatible with these devices - Apple Support

does not list iPhone 6Plus, so 12.5.7 may be already as high as your iPhone can go.

About iOS 12 Updates - Apple Support says the latest iOS12 version is iOS 12.5.7

All the best.